Patent Publication Number: US-2022213926-A1

Title: Bearing assemblies, related bearing apparatuses and related methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/644,383 filed 4 Mar. 2020 which is a U.S. Nationalization of PCT International Application No. PCT/US2019/037191 filed on 14 Jun. 2019, which claims priority to U.S. Provisional Application No. 62/684,044 filed on 19 Jun. 2018, the disclosure of each of the foregoing applications which is incorporated herein, in its entirety, by this reference. 
    
    
     BACKGROUND 
     Wear-resistant, superhard compacts are utilized in a variety of mechanical applications. For example, polycrystalline diamond compacts (“PDCs”) are used in drilling tools (e.g., cutting elements, gage trimmers, etc.), machining equipment, bearing apparatuses, wire-drawing machinery, and in other mechanical apparatuses. 
     PDCs and other superhard compacts have found particular utility as superhard bearing elements in thrust bearings within pumps, turbines, subterranean drilling systems, motors, compressors, generators, gearboxes, and other systems and apparatuses. For example, a PDC bearing element typically includes a superhard diamond layer that is commonly referred to as a diamond table. The diamond table is formed and bonded to a substrate using a high-pressure/high-temperature (“HPHT”) process. 
     Despite the availability of a number of different bearing apparatuses including such PDCs and/or other superhard materials, manufacturers and users of bearing apparatuses continue to seek bearing apparatuses that exhibit improved performance characteristics, lower cost, or both. 
     SUMMARY 
     Embodiments disclosed herein are directed to bearing assemblies, related bearing apparatuses, and related methods. In an embodiment, a bearing assembly is disclosed. The bearing assembly includes a support structure having a first end and a second end. The support structure defines a support structure conduit extending from the second end to the first end. The bearing assembly also includes a superhard bearing element secured to the support structure. The superhard bearing element includes a superhard sealing surface, a base surface, at least one lateral surface extending between the superhard sealing surface and the base surface, at least one interior surface extending between the superhard sealing surface to the base surface, and a plurality of fins. The at least one interior surface defines a bearing element conduit coupled to the support structure conduit. The plurality of fins are separated from each other by a plurality of grooves formed in at least one of the at least one lateral surface, the interior surface, or the support structure. 
     In an embodiment, a bearing assembly is disclosed. The bearing assembly includes a support structure having a first end and a second end. The support structure defines a support structure conduit extending from the second end to the first end. The bearing assembly also includes a superhard bearing element secured to the support structure. The superhard bearing element includes an at least partially leached polycrystalline diamond table defining a superhard sealing surface. The at least partially leached polycrystalline diamond table includes a leached region extending inwardly from the superhard sealing surface. The superhard bearing elements also includes a base surface, at least one lateral surface extending between the superhard sealing surface and the base surface, and at least one interior surface extending between the superhard sealing surface to the base surface. The at least one interior surface defines a bearing element conduit coupled to the support structure conduit. 
     In an embodiment, a bearing assembly is disclosed. The bearing assembly includes a support structure having a first end and a second end. The support structure defines a support structure conduit extending from the second end to the first end. The support structure defines a recess at the first end thereof. The bearing assembly also includes a superhard bearing element at least partially disposed in and press-fit or brazed in the recess. The superhard bearing element includes a superhard sealing surface, a base surface, at least one lateral surface extending between the superhard sealing surface and the base surface, and at least one interior surface extending between the superhard sealing surface to the base surface. The at least one interior surface defines a bearing element conduit coupled to the support structure conduit. 
     In an embodiment, a bearing assembly is disclosed. The bearing assembly includes a support structure having a first end and a second end. The support structure defines a support structure conduit extending from the second end to the first end. The bearing assembly also includes a superhard bearing element secured to the support structure. The superhard bearing element includes a superhard sealing surface exhibiting a surface roughness, in root mean square, of about 5 μm to about 40 μm, a base surface, at least one lateral surface extending between the superhard sealing surface and the base surface, and at least one interior surface extending between the superhard sealing surface to the base surface. The at least one interior surface defines a bearing element conduit coupled to the support structure conduit. 
     In an embodiment, a bearing apparatus is disclosed. The bearing apparatus includes a stator bearing assembly and a rotor bearing assembly that contacts and is configured to rotate relative to the stator bearing assembly. At least one of the stator bearing assembly or the rotor bearing assembly is any one of the bearing assemblies disclosed herein. 
     In an embodiment, a method of operating a bearing apparatus is disclosed. The method includes rotating a rotor bearing assembly relative to a stator bearing assembly. The rotor bearing assembly includes a rotor support structure and a rotor bearing element secured to the rotor support structure. The stator bearing assembly includes a stator support structure and a stator bearing element secured to the stator support structure. The rotor bearing element includes a first superhard sealing surface and the stator bearing element including a second superhard sealing surface. The first superhard sealing surface contacts and the second superhard sealing surface. The method also includes flowing a fluid through each of a stator support structure conduit defined by at least one inner support structure surface of the stator support structure, a stator bearing element conduit that is defined by at least one stator interior surface of the second superhard bearing element, a rotor support structure conduit defined by at least one inner support structure surface of the rotor support structure, and a rotor bearing element conduit that is defined by at least one rotor interior surface of the first superhard bearing element. The stator bearing element conduit extends between the second superhard sealing surface and the stator base surface and the rotor bearing element conduit extends between the first superhard sealing surface and the rotor base surface. 
     Features from any of the disclosed embodiments may be used in combination with one another, without limitation. In addition, other features and advantages of the present disclosure will become apparent to those of ordinary skill in the art through consideration of the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings illustrate several embodiments of the present disclosure, wherein identical reference numerals refer to identical or similar elements or features in different views or embodiments shown in the drawings. 
         FIGS. 1A and 1B  are an isometric and schematic cross-sectional views, respectively, of a bearing assembly, according to an embodiment. 
         FIG. 2A  is a cross-sectional view of a superhard bearing element, according to an embodiment. 
         FIG. 2B  is a cross-sectional view of a superhard bearing element, according to an embodiment. 
         FIGS. 3A to 3C  are cross-sectional views of different superhard bearing elements, according to different embodiments. 
         FIGS. 4A and 4B  are a side view and a top plan view of a superhard bearing element shown with respect to a central axis, according to an embodiment. 
         FIGS. 4C and 4D  are a side view and a top plan view of a superhard bearing element shown with respect to a central axis, according to an embodiment. 
         FIGS. 4E and 4F  are a side view and a top plan view of a superhard bearing element shown with respect to a central axis, according to an embodiment. 
         FIGS. 4G and 4H  are a side view and a top plan view of a superhard bearing element shown with respect to a central axis, according to an embodiment. 
         FIGS. 4I and 4J  are a side cross-sectional view and a top plan view of a superhard bearing element shown with respect to a central axis, according to an embodiment. 
         FIGS. 4K and 4L  are a side view and a top plan view of a superhard bearing element shown with respect to a central axis, according to an embodiment. 
         FIGS. 4M and 4N  are a side view and a top plan view of a superhard bearing element shown with respect to a central axis, according to an embodiment. 
         FIGS. 4P and 4Q  are a side view and a top plan view of a superhard bearing element shown with respect to a central axis, according to an embodiment. 
         FIG. 5  is a side cross-sectional view of a portion of a bearing apparatus, according to any embodiment. 
         FIG. 6  is a side cross-sectional view of a portion of a bearing apparatus, according to any embodiment. 
         FIGS. 7A and 7B  are a schematic cross-sectional view and a top plan view, respectively, of a bearing assembly, according to an embodiment. 
         FIGS. 8A and 8B  are a schematic cross-sectional view and a top plan view, respectively, of a bearing assembly, according to an embodiment. 
         FIG. 9  is a schematic cross-sectional view of a bearing apparatus, according to an embodiment. 
         FIG. 10  is a schematic cross-sectional view of a bearing apparatus, according to an embodiment. 
         FIG. 11  is a schematic cross-sectional view of a bearing apparatus, according to an embodiment. 
         FIG. 12  is a side cross-sectional view of a portion of a bearing apparatus, according to an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments disclosed herein are directed to bearing assemblies, related bearing apparatuses (e.g., rotary union bearing apparatuses), and related methods. In one or more embodiments, a bearing assembly may include a support structure having a first end and a second end. The bearing assembly also includes a superhard bearing element secured to the first end of the support structure. The superhard bearing element includes a superhard sealing surface that may be configured to contact a sealing surface of an opposing bearing element, a base surface contacting the support structure and opposing the superhard sealing surface, and at least one lateral surface extending between the superhard sealing surface and the base surface. The support structure and the superhard bearing element may both include at least one conduit extending therethrough through which a fluid may flow. For example, the support structure may include a support structure conduit extending from the second end towards the first end and the superhard bearing element may include a bearing element conduit extending therethrough. The bearing element conduit may be defined by at least one interior surface of the bearing element that extends between the superhard sealing surface and the base surface. The support structure conduit and the bearing element conduit are coupled together thereby enabling a fluid to flow through the bearing assembly. 
     The bearing assemblies disclosed herein may be used in a bearing apparatus. The bearing apparatus may include a stator bearing assembly and a rotor bearing assembly that is configured to rotate relative to the stator bearing assembly. In an embodiment, both the stator bearing assembly and the rotor bearing assembly may include a support structure and a superhard bearing element secured to the support structure. Each of the superhard bearing elements of the stator bearing assembly and the rotor bearing assembly may include superhard sealing surfaces that are configured to contact each other. The stator bearing assembly and the rotor bearing assembly may each have at least one conduit extending therethrough. The conduits of the stator bearing assembly and the rotor bearing assembly may be coupled together and configured to allow a fluid to flow between the stator bearing assembly and the rotor bearing assembly, even when the rotor bearing assembly is rotating relative to the stator bearing assembly. In an embodiment, the superhard sealing surfaces of the stator bearing assembly and the rotor bearing assembly can substantially limit or prevent the fluid flowing between the stator bearing assembly and the rotor bearing assembly from leaking from the conduits. 
     Due to the conduits of the bearing assemblies disclosed herein, the bearing assemblies and related bearing apparatuses may be used in rotary unions. However, the bearing assemblies and related bearing apparatuses disclosed herein may be an improvement over conventional rotary unions. For example, conventional rotary unions including non-superhard sealing surfaces may not adequately prevent fluids from leaking between the non-superhard sealing surfaces thereof, especially after long periods of operation. As such, conventional rotary unions may use of O-rings or other sealing devices to prevent the fluid from leaking from the rotary union. However, the use of O-rings and other sealing devices may at least one of increase the complexity of the rotary union, exhibit short life spans, increase friction between the rotating and stationary components of the rotary union thereby increasing the energy required to use the rotary union, or increase the size of the rotary union. However, the bearing assemblies and bearing apparatuses disclosed herein do not require the use of O-rings or other sealing devices because, as previously discussed, the superhard sealing surfaces thereof may substantially prevent or limit a fluid from leaking between the superhard sealing surfaces thereof. 
     In an embodiment, substantially preventing or limiting the fluid from leaking between the superhard sealing surfaces may cause the bearing assemblies and bearing apparatuses disclosed herein to generate significant amounts of heat during operation. For example, allowing the fluid to leak between the superhard sealing surfaces can cause the superhard sealing surfaces to transfer heat to the fluid and/or the fluid can form a thin fluid film which limits or prevents the superhard sealing surfaces from contacting each other. However, preventing or limiting the fluid from leaking between the superhard sealing surfaces may cause the superhard sealing surfaces to directly contact each other during operation which may generate heat. The heat generated during operation of the bearing assemblies and bearing apparatuses disclosed herein may cause damage to the bearing assemblies and bearing apparatuses disclosed herein. As such, as will be discussed in more detail below, the bearing assemblies and bearing apparatuses disclosed herein may include thermal management features that at least one of may improve cooling of the superhard bearing elements, limit the amount of heat generated by the superhard bearing elements, or improve the thermal resistance of the bearing assemblies and bearing apparatuses. 
       FIGS. 1A and 1B  are isometric and schematic cross-sectional views, respectively, of a bearing assembly  100 , according to an embodiment. The bearing assembly  100  includes a support structure  102  that includes a first end  104  and a second end  106 . The bearing assembly  100  also includes a superhard bearing element  108  secured to the support structure  102 . The superhard bearing element  108  include a superhard sealing surface  110 , a base surface  112  (shown in  FIG. 1B ) that opposes the superhard sealing surface  110 , and at least one lateral surface  114  extend between the superhard sealing surface  110  and the base surface  112 . 
     The support structure  102  and the superhard bearing element  108  collectively define at least one conduit  116  extending through the bearing assembly  100 . The conduit  116  allows fluid to flow through the bearing assembly  100 . Referring to  FIG. 1B , the at least one conduit  116  includes a support structure conduit  116 A and a bearing element conduit  116 B. The support structure conduit  116 A may extend from the second end  106  of the support structure  102  generally towards the first end  104  of the support structure  102 . For example, the support structure  102  may include a support structure interior surface  118  that extends from the second end  106  generally towards the first end  104 . The support structure interior surface  118  may define the support structure conduit  116 A. The bearing element conduit  116 B may extend from superhard sealing surface  110  to the base surface  112  of the superhard bearing element  108 . For example, the superhard bearing element  108  may include a bearing element interior surface  120  that extends between the superhard sealing surface  110  and the base surface  112 . The bearing element interior surface  120  may define the bearing element conduit  116 B. 
     The support structure conduit  116 A and the bearing element conduit  116 B may be positioned such that a fluid flowing through the support structure conduit  116 A can also communicate or flow through the bearing element conduit  116 B, and vice versa. In an embodiment, the support structure conduit  116 A and the bearing element conduit  116 B may exhibit substantially the same size and shape and be positioned such that the support structure interior surface  118  and the bearing element interior surface  120  are substantially aligned, continuous, and/or congruent with each other. In such an embodiment, the conduit  116  may include substantially no recesses, ridges, protrusions, etc. at the intersection of the support structure conduit  116 A and the bearing element conduit  116 B which can impede fluid flow through the conduit  116 . In another embodiment, the support structure conduit  116 A and the bearing element conduit  116 B may be sized and positioned such that the support structure interior surface  118  and the bearing element interior surface  120  are incongruent, misaligned, and/or discontinuous with each other. For example, the support structure conduit  116 A may exhibit a size or shape that is different than the bearing element conduit  116 B and/or the support structure conduit  116 A and the bearing element conduit  116 B are not positioned to be congruent with each other. In such an embodiment, the conduit  116  may include recesses, ridges, protrusion, etc. which can slow or otherwise impede the flow of a fluid through the conduit  116 . 
     In an embodiment, one or more of the support structure conduit  116 A or the bearing element conduit  116 B may exhibit a diameter or lateral dimension that is greater than about 1 mm, greater than about 2 mm, greater than about 5 mm, greater than about 10 mm, greater than about 15 mm, or in ranges of about 1 mm to about 2 mm, about 1.5 mm to about 3 mm, about 2 mm to about 4 mm, about 2.5 mm to about 5 mm, about 4 mm to about 6 mm, about 5 mm to about 7.5, about 6 mm to about 8 mm, about 7.5 mm to about 10 mm, about 8 mm to about 12 mm, or about 10 mm to about 15 mm. The diameter of the support structure conduit  116 A and/or the bearing element conduit  116 B may depend on one or more of the amount of fluid expected to flow through the conduit  116 , the expected pressure to be applied between the superhard sealing surface  110  and an opposing sealing surface, the diameter of the superhard bearing element  108 , the diameter of the support structure  102 , or other factors. In an embodiment, the support structure conduit  116 A and the bearing element conduit  116 B may exhibit the same diameter. In such an embodiment, the intersection of the support structure conduit  116 A and the bearing element conduit  116 B may not impede the flow of the fluid. In an embodiment, the support structure conduit  116 A and the bearing element conduit  116 B exhibit different diameters. In such an embodiment, the intersection of the support structure conduit  116 A and the bearing element conduit  116 B may impede the flow of the fluid. 
     The support structure  102  may exhibit any suitable shape that is sufficient to enable the superhard bearing element  108  secured thereto and define the support structure conduit  116 A extending therethrough. In an embodiment, the support structure  102  may exhibit a shape that generally corresponds to the shape of the conduit  116 . For example, the support structure  102  may exhibit a generally cylindrical shape. In an embodiment, the support structure  102  may include a first portion  122  extending from the first end  104  and a second portion  124  extending from the second end  106  towards the first portion  122 . The first portion  122  may exhibit an elongated or non-elongated shape. The first portion  122  may exhibit a first diameter that is larger than the support structure conduit  116 A. As such, the support structure conduit  116 A may extend through the first portion  122 . The second portion  124  may exhibit a second diameter or lateral dimension that is greater than the first diameter or lateral dimension of the first portion  122 . The larger second diameter of the second portion  124  may facilitate attachment of the bearing assembly  100  to another component. For example, the second portion  124  may define holes  126  ( FIG. 1A ) therein that may enable the bearing assembly  100  to be attached to another component (e.g., with screws or other suitable fastener). 
     The superhard bearing element  108  may exhibit a diameter or lateral dimension that is greater than the diameter or lateral dimension of the bearing element conduit  116 B. For example, the superhard bearing element  108  can exhibit a diameter or lateral dimension that is greater than about 2 mm, greater than about 5 mm, greater than about 7.5 mm, greater than about 10 mm, greater than about 25 mm, greater than about 50 mm, greater than about 75 mm, greater than about 100 mm, greater than about 125 mm, greater than about 150 mm, greater than about 200 mm, greater than about 200 mm, or in ranges of about 2 mm to about 5 mm, about 2.5 mm to about 7.5 mm, about 5 mm to about 10 mm, about 7.5 mm to about 15 mm, about 10 mm to about 25 mm, about 20 mm to about 50 mm, about 25 mm to about 75 mm, about 50 mm to about 100 mm, about 75 mm to about 150 mm, or about 100 mm to about 200 mm. In an embodiment, the diameter of the superhard bearing element  108  is at least about 1.5× greater (e.g., at least about 2× greater, at least about 3× greater, or at least about 5× greater) than the diameter of the bearing element conduit  116 B. In such an embodiment, the superhard sealing surface  110  may exhibit a suitable surface area to support thrust loads applied thereto during operation. 
     The support structure conduit  116 A and the bearing element conduit  116 B may be formed in the support structure  102  and the superhard bearing element  108 , respectively, using a variety of techniques. In an embodiment, the support structure conduit  116 A and/or the bearing element conduit  116 B may be formed by electrical discharge machining (e.g., plunge electrical discharge machining and/or wire electrical discharge machining), drilling, laser drilling, other suitable techniques, or combinations thereof. In an embodiment, the support structure  102  may be casted, molded, or otherwise formed to include the support structure conduit  116 A. In an embodiment, at least one of the support structure  102  or the superhard bearing element  108  includes a sacrificial material substantially defining the support structure conduit  116 A or the bearing element conduit  116 B. For example, at least one the support structure  102  or the superhard bearing element  108  may be formed by laterally surrounding a sacrificial material (e.g., tungsten, tungsten carbide, hexagonal boron nitride, combinations thereof) with a material (e.g., particles or sintered, solid material) and then forming the support structure  102  or the superhard bearing element  108  using a suitable technique (e.g., an HPHT process). After forming the support structure  102  or the superhard bearing element  108 , the sacrificial material may be removed therefrom. 
     The superhard bearing element  108  may be secured to the support structure  102  using any suitable method. For example, the first end  104  of the support structure  102  may define a recess  128  therein. The recess  128  may generally correspond to the size and shape of the superhard bearing element  108 . In an embodiment, the superhard bearing element  108  may be at least partially disposed in and secured to the recess  128 . For example, the superhard bearing element  108  may be brazed to the recess  128 . In another example, the superhard bearing element  108  may be press-fit into the recess  128  (with any acceptable interference fit, without limitation). 
     The support structure  102  may include one or more materials or combinations of materials. For example, the support structure  102  may include a metal, alloy steel, a metal alloy, carbon steel, stainless steel, tungsten carbide, other suitable conductive materials, other suitable non-conductive materials, or combinations thereof. In any event, the support structure  102  may include a suitable material having sufficient mechanical properties (e.g., strength and resilience) to support the superhard bearing element  108 . 
     The superhard bearing element  108  may include one or more superhard materials. The term “superhard” means a material having a hardness at least equal to the hardness of tungsten carbide. In an embodiment, the superhard bearing element  108  may include polycrystalline cubic boron nitride, polycrystalline diamond (e.g., formed by chemical vapor deposition or by HPHT sintering), diamond crystals, silicon carbide, silicon nitride, tantalum carbide, tungsten carbide (e.g., binderless tungsten carbide, cobalt-cemented tungsten carbide), boron carbide, other metal carbides, other superhard ceramic carbides, or combinations thereof. In another embodiment, each of the superhard bearing element  108  may comprise reaction-bonded silicon carbide or reaction-bonded silicon nitride. The reaction-bonded silicon carbide or reaction-bonded silicon nitride may have additional materials therein. For example, the additional materials in the reaction-bonded superhard ceramic may include diamond, polycrystalline diamond, cubic boron nitride, a material exhibiting a hardness greater than the reaction-bonded ceramic or a material exhibiting a thermal conductivity greater than the reaction-bonded ceramic. Adding materials to the reaction-bonded ceramic comprising the superhard bearing element  108  may increase the thermal conductivity and/or wear resistance of the superhard bearing element  108 . For example, adding diamond particles to reaction-bonded silicon carbide or reaction-bonded silicon nitride may increase the wear resistance of the superhard bearing element  108  by more than 500%. In an embodiment, diamond may be added to the reaction-bonded ceramic in an amount less that about 80 weight % (e.g., about 80 weight % to about 50 weight %, about 50 weight % to about 25 weight %, less than about 25 weight %). Suitable reaction-bonded ceramics are commercially available from M Cubed Technologies, Inc. of Newark, Del. In an embodiment, the superhard bearing element  108  may be formed from a single material. 
     As shown in  FIG. 1B , the superhard bearing element  108  may include a superhard table  130  defining the superhard sealing surface  110  and a substrate  132  to which the superhard table  130  is bonded. In an embodiment, the superhard bearing element  108  may comprise a polycrystalline diamond compact (“PDC”) includes a polycrystalline diamond (“PCD”) table defining the superhard table  130  to which the substrate  132  is bonded. For example, the substrate  132  may comprise a cobalt-cemented tungsten carbide substrate bonded to a PCD table. The PCD table includes a plurality of directly bonded-together diamond grains exhibiting diamond-to-diamond bonding therebetween (e.g., sp 3  bonding), which define a plurality of interstitial regions. A portion of, or substantially all of, the interstitial regions of the PCD table may include a metal-solvent catalyst or a metallic interstitial constituent disposed therein that is infiltrated from the substrate  132  or infiltrated or provided from another source (e.g., mixed with diamond particles prior to HPHT sintering) during fabrication. For example, the metal-solvent catalyst or metallic interstitial constituent may be selected from iron, nickel, cobalt, and alloys of the foregoing. As will be discussed in more detail below, the PCD table may further include leached diamond in which the metal-solvent catalyst or metallic interstitial constituent has been partially or substantially completely depleted from a selected surface or volume of the PCD table, such as via a leaching process. PCD may also be sintered with one or more alkali metal or a alkaline earth metal catalysts (e.g., alkali metal or alkaline earth metal carbonates). 
     In an embodiment, the PDC may be formed in an HPHT process. For example, diamond particles may be disposed adjacent to the substrate  132 , and subjected to an HPHT process to sinter the diamond particles to form the PCD table and bond the PCD table to the substrate  132 , thereby forming the PDC. The temperature of the HPHT process may be at least about 1000° C. (e.g., about 1200° C. to about 1600° C.) and the cell pressure of the HPHT process may be at least 4.0 GPa (e.g., about 5 GPa to about 12 GPa or about 7.5 GPa to about 11 GPa) for a time sufficient to sinter the diamond particles. 
     The diamond particles may exhibit an average particle size of about 50 μm or less, such as about 30 μm or less, about 20 μm or less, about 10 μm to about 18 μm, or about 15 μm to about 18 μm. In some embodiments, the average particle size of the diamond particles may be about 10 μm or less, such as about 2 μm to about 5 μm or submicron. In some embodiments, the diamond particles may comprise a relatively larger size and at least one relatively smaller size. As used herein, the phrases “relatively larger” and “relatively smaller” refer to particle sizes (by any suitable method) that differ by at least a factor of two (e.g., 30 μm and 15 μm). According to various embodiments, the mass of diamond particles may include a portion exhibiting a relatively larger size (e.g., 30 μm, 20 μm, 15 μm, 12 μm, 10 μm, 8 μm) and another portion exhibiting at least one relatively smaller size (e.g., 6 μm, 5 μm, 4 μm, 3 μm, 2 μm, 1 μm, 0.5 μm, less than 0.5 μm, 0.1 μm, less than 0.1 μm). In an embodiment, the diamond particles may include a portion exhibiting a relatively larger size between about 10 μm and about 40 μm and another portion exhibiting a relatively smaller size between about 1 μm and 4 μm. In some embodiments, the diamond particles may comprise three or more different sizes (e.g., one relatively larger size and two or more relatively smaller sizes), without limitation. The PCD table so-formed after sintering may exhibit an average diamond grain size that is the same or similar to any of the foregoing diamond particle sizes and distributions. 
     More details about diamond particle sizes and diamond particle size distributions that may be employed are disclosed in U.S. Pat. No. 9,346,149; U.S. Provisional Patent Application No. 61/948,970; and U.S. Provisional Patent Application No. 62/002,001. Each of U.S. patent application Ser. No. 13/734,354; U.S. Provisional Patent Application No. 61/948,970; and U.S. Provisional Patent Application No. 62/002,001 is incorporated herein, in its entirety, by this reference. Further, additional examples of PDCs and PCD tables and methods to form the PDCs and the PCD tables that may be employed in any of the embodiments disclosed herein are disclosed in U.S. Pat. Nos. 7,866,418, 8,297,382, and 9,315,881, the disclosure of each of which are incorporated herein, in its entirety, by this reference. 
     In an embodiment, the superhard table  130  may be integrally formed with the substrate  132 . For example, the superhard table  130  may be a sintered PCD table that is integrally formed with or upon the substrate  132 . In such an embodiment, the infiltrated metal-solvent catalyst from the substrate  132  may be used to catalyze formation of diamond-to-diamond bonding between diamond grains of the superhard table  130  from diamond powder during HPHT processing. In another embodiment, the superhard table  130  may be a pre-formed superhard table that has been HPHT bonded to the substrate  132  in a second HPHT process after being initially formed in a first HPHT process. For example, the superhard table  130  may be a pre-formed PCD table that has been at least partially leached to substantially completely remove the metal-solvent catalyst used in the manufacture thereof and subsequently HPHT bonded or brazed to the substrate  132  in a separate process. 
     The substrate  132  may be formed from any number of different materials, and may be integrally formed with, or otherwise bonded or connected to, the superhard table  130 . Materials suitable for the substrate  132  may include, without limitation, cemented carbides, such as tungsten carbide, titanium carbide, chromium carbide, niobium carbide, tantalum carbide, vanadium carbide, or combinations thereof cemented with iron, nickel, cobalt, or alloys thereof. For example, in an embodiment, the substrate  132  comprises cobalt-cemented tungsten carbide. However, in certain embodiments, the superhard table  130  may be omitted, and the superhard bearing element  108  may be made from a superhard material, such as cobalt-cemented tungsten carbide. In other embodiments, the substrate  132  may be omitted and the superhard bearing element  108  may be a superhard material, such as a polycrystalline diamond body that has been at least partially leached to deplete the metal-solvent catalyst therefrom or may be an un-leached PCD body. 
     In another embodiment, the superhard material of the superhard bearing element  108  may be a superhard coating that forms the superhard sealing surface  110 . The coating may be formed using a chemical vapor deposition technique, a physical vapor deposition technique, or any other deposition technique. For example, diamond may be deposited on a less hard surface to form the superhard sealing surface  110  using a chemical or physical vapor deposition technique. 
     The superhard sealing surface  110  may include a relatively smooth surface which can substantially prevent leaks across the superhard sealing surface  110 . For example, contacting the superhard sealing surface  110  against an opposing sealing surface substantially prevent or limit fluid flowing between the superhard sealing surface  110  and the opposing sealing surface because of the relatively smooth surface of the superhard sealing surface  110 . The superhard sealing surface  110  may maintain the relatively smooth surface thereof during operation for long periods of time because the superhard sealing surface  110  includes a superhard material. The superhard sealing surface  110  may exhibit a relatively smooth surface when the superhard sealing surface  110  exhibits a surface roughness (in root mean square) that is less than about 100 such as less than or less than 50 It is noted that the opposing sealing surface may also include a relatively smooth surface thereby further preventing or limiting fluid flow the superhard sealing surface  110  and the opposing sealing surface. 
     However, as previously discussed, substantially preventing fluids from leaking across the superhard sealing surface  110  may cause the superhard bearing element  108  to generate heat during operation. The heat generated by the superhard sealing surface  110  may be generated by friction. To limit heat generated by superhard sealing surface  110 , in an embodiment, the superhard sealing surface  110  may exhibit a relatively smooth surface finish. In other words, the relatively smooth surface finish of the superhard sealing surface  110  may be a thermal management feature of the bearing assembly  100  since it may reduce the amount of heat generated by the superhard bearing element  108  during operation. In an embodiment, the relatively smooth surface finish includes a surface roughness that is less than about 40 μm. As such, the superhard sealing surface  110  may exhibit a surface roughness, in root mean square, that is less than about 40 μm, less than about 30 μm, less than about 20 μm, less than about 10 μm, less than about 5 μm, less than about 1 μm, submicron, about 5 μm to about 40 μm, about 5 μm to about 20 μm, about 10 μm to about 30 μm, or about 20 μm to about 40 μm. The superhard sealing surface  110  may maintain the relatively smooth surface finish for long periods of time because the superhard sealing surface  110  includes a superhard material. It is noted that the opposing sealing surface may also include a relatively smooth surface finish thereby further reducing the amount of heat generated during operation. 
     The superhard sealing surface  110  may be processed to exhibit a relatively smooth surface finish using any suitable method. In an embodiment, the superhard sealing surface  110  may be smoothed by polishing, lapping, grinding, lasing the superhard sealing surface  110 , or combinations thereof. 
       FIG. 2A  is a cross-sectional view of a superhard bearing element  208 A, according to an embodiment. In an embodiment, at least one feature of the superhard bearing element  208 A may be the same as or substantially similar to at least one feature of any of the superhard bearing elements disclosed herein. For example, the superhard bearing element  208 A may include a superhard table  230 A, a substrate  232 A, and a conduit  216 A. Further, the superhard bearing element  208 A may be used in any of the bearing assemblies or bearing apparatuses disclosed herein. 
     The superhard table  230 A may include a plurality of superhard particles that are bonded together. The superhard particles may define a plurality of interstitial regions that are at least partially occupied by an interstitial constituent. For example, the interstitial constituent may include a metal-solvent catalyst when the superhard particles includes diamond grains. In an embodiment, the superhard table  230 A may be at least partially leached to deplete the interstitial constituent therefrom in order to enhance the thermal stability of the superhard table  230 A. Leaching the superhard table  230 A may form a leached region  234  that had at least some of the interstitial constituent removed therefrom and an unleached region  236  adjacent to the substrate  232 A that was not leached. The unleached region  236  may cause the superhard table  230 A to remain securely bonded to the substrate  232 A and prevent damage to the substrate  232 A. The leached region  234  may be a thermal management feature of the superhard bearing element  208 A. For example, the superhard bearing element  208 A may include a PCD table bonded to the substrate  232 A. The PCD table may include a metal-solvent catalyst (e.g., iron, nickel, cobalt, or alloys thereof) or another suitable catalyst disposed in the interstitial regions thereof. The metal-solvent catalyst may reduce the thermal stability of the PCD table. As such, the metal-solvent catalyst may be removed from a portion of the PCD table thereby improving the thermal stability thereof. It is noted that the superhard table  230 A may be leached even when the superhard bearing element  208 A includes one or more thermal management features. 
     The leached region  234  may extend inwardly from at least the superhard sealing surface  210 A of the superhard bearing element  208 A to a selected depth. In an embodiment, the depth of the leached region  234  may be about 20 μm to about 600 μm, about 400 μm to about 1200 μm, about 400 μm to about 800 μm, about 600 μm to about 1000 μm, or greater than about 1000 μm. 
     Typically, the superhard table  230 A is leached by immersing at least a portion of the superhard table  230 A in a leaching solution. The leaching solution may include any suitable acid, such as aqua regia, nitric acid, hydrofluoric acid, or mixture thereof. In an embodiment, the leached region  234  may extend inwardly to a depth (e.g., generally uniform depth or variable depth) from one or more surfaces of the superhard table  230 A that contacts the leaching solution. As such, the superhard table  230 A may be configured to exhibit a selected leached profile (e.g., the leached region  234  exhibits a selected shape) depending on which surfaces of the superhard table  230 A are exposed to the leaching solution. In an embodiment, only the superhard sealing surface  210 A is exposed to the leaching solution and, as such, the leached region  234  may extend inwardly from the superhard sealing surface  210 A. In an embodiment, the superhard sealing surface  210 A and a portion of at least one lateral surface  214  of the superhard table  230 A is exposed to the leaching solution. In such an embodiment, the leached region  234  may extend inwardly from the superhard sealing surface  210 A and the lateral surface  214 . In an embodiment, the superhard table  230 A may include a chamfer  238  that was formed in the superhard table  230 A before the superhard table  230 A was leached. In such an embodiment, the leached region  234 A may extend inwardly from the chamfer  238  to a leach depth along with any other surface of the superhard table  230 A that was exposed to the leaching solution. In an embodiment, the superhard table  230 A may include a chamfer  238  that is formed in the superhard table  230 A after the superhard table  230 A leached. In such an embodiment, the depth and/or shape of the portions of the leached region  234  at or near the chamfer  238  may be affected. 
     In an embodiment, the superhard table  230 A is leached after forming the conduit  216 A therein. The conduit  216  is defined by an interior surface  220  of the superhard bearing element  208 A. In such an embodiment, a portion of the leached region  234  may extend inwardly from a portion of the interior surface  220  that is spaced from the substrate  232 A for the selected depth along with any other surface of the superhard table  230 A that was exposed to the leaching solution. For example, the portions of the superhard table  230 A adjacent to the bearing element interior surface  220  may exhibit relatively high temperature during operation. As such, leaching the superhard table  230 A such that the leached region  234  extends inwardly from at least a portion of the bearing element interior surface  220  may inhibit thermal damage to the superhard table  230 A. 
       FIG. 2B  is a schematic cross-sectional view of a superhard bearing element  208 B, according to an embodiment. In an embodiment, at least one feature of the superhard bearing element  208 B may be the same as or substantially similar to at least one feature of any of the superhard bearing elements disclosed herein. For example, the superhard bearing element  208 B may include a superhard table  230 B defining a superhard sealing surface  210 B, a substrate  232 B, and a conduit  216 B. Further, the superhard bearing element  208 B may be used in any of the bearing assemblies or bearing apparatuses disclosed herein. 
     The superhard bearing element  208 B includes a plurality of superhard particles defining a plurality of interstitial regions. At least a portion of the interstitial regions of the superhard bearing element  208 B includes an interstitial constituent disposed therein. However, the superhard table  230 A is not leached (i.e., does not include a leached region). In an embodiment, the superhard bearing element  208 B may include one or more thermal management features that make leaching the superhard table  230 B unnecessary. 
       FIGS. 3A to 3C  are schematic cross-sectional views of different superhard bearing elements, according to different embodiments. In an embodiment, at least one of the features of the superhard bearing elements illustrated in  FIGS. 3A-3C  may be the same as or substantially similar to at least one feature of any of the superhard bearing elements disclosed herein. For example, each of the superhard bearing elements illustrated in  FIGS. 3A-3C  may include a superhard table, a substrate, and a conduit. Further, the superhard bearing elements illustrated in  FIGS. 3A-3C  may be used in any of the bearing assemblies or bearing apparatuses disclosed herein. 
     Referring to  FIG. 3A , a superhard bearing element  308 A includes a superhard sealing surface  310 A, an base surface  312 A, and at least one lateral surface  314 A extending from the base surface  312 A to the superhard sealing surface  310 A. The superhard sealing surface  310 A and the lateral surface  314 A may intersect with each other substantially at a right angle. However, configuring the superhard sealing surface  310 A and the lateral surface  314 A to intersect substantially at a right angle may cause the superhard bearing element  308 A to be damages under certain conditions during operation. 
     Referring to  FIG. 3B , a superhard bearing element  308 B includes a superhard sealing surface  310 B, an base surface  312 B, and at least one lateral surface  314 B extending from the base surface  312 B towards the superhard sealing surface  310 B. The superhard bearing element  308 B also includes a chamfer  338 B extending between the superhard sealing surface  310 B and the lateral surface  314 B. The chamfer  338 B may prevent or reduce damage to of the superhard bearing element  308 B during operation. It is noted that the superhard bearing element  308 B may include a curved surface or another suitable surface instead of the chamfer  338 B. 
     Referring to  FIG. 3C , a superhard bearing element  308 C includes a bearing element interior surface  320  that defines a conduit  316 . The superhard bearing element  308 C may include an interior chamfer  344  extending between the interior surface  320  and the superhard sealing surface  310 C. The interior surface  320  may extend from the interior chamber  344  of the superhard bearing element  308 C to a base surface  312 C of the superhard bearing element  308 C. The interior chamfer  344  may reduce damage to the superhard bearing element  308 C during operation and/or facilitate fluid flow between the conduit  316  and the conduit of an opposing bearing element. Further, the interior chamfer  344  may form a thermal management feature of the superhard bearing element  308 C because the interior chamfer  344  increases the surface area of the superhard bearing element  308 C that is exposed to the fluid flowing through the conduit  316  thereby increasing the amount of heat that may be transferred to the fluid. The superhard bearing element  308 C may also include an exterior chamfer  338 C extending between the lateral surface  314 C and the superhard sealing surface  310 C. 
     In an embodiment, the one or more thermal management features of any of the superhard bearing elements disclosed may include a plurality of fins formed in or coupled to at least a portion of the lateral surface or the bearing element interior surface thereof. For example, the plurality of fins of the superhard bearing elements may increase the surface area of the superhard bearing elements that are at least one of exposed to an environment (e.g., a gas, solid, or liquid) about the bearing element, exposed to a fluid flow (e.g., a gas or liquid) around or through the superhard bearing element, or contact the support structure. The increased surface area of superhard bearing elements created by the plurality of fins can increase the amount of heat that is transferred from the superhard bearing element into at least one of the environment, the fluid, or the support structure. The increased amount of heat transferred from the superhard bearing element can decrease the temperature of the superhard bearing element during operation. 
       FIGS. 4A-4P  illustrate a various different superhard bearing elements that each includes a plurality of fins, according to different embodiments. In an embodiment, at least one feature of the superhard bearing elements illustrated in  FIGS. 4A-4P  may be the same as or similar to at least one feature of any of the superhard bearing element disclosed herein. Further, the superhard bearing elements illustrated in  FIGS. 4A-4P  may be used in any of the bearing assemblies or bearing apparatuses disclosed herein. 
       FIGS. 4A and 4B  are a side view and a top plan view of a superhard bearing element  408 A shown with respect to a central axis  442 A, according to an embodiment. 
     The superhard bearing element  408 A may include at least one lateral surface  414 A extending between a superhard sealing surface  410 A and a base surface  412 A of the superhard bearing element  408 A. The superhard bearing element  408 A includes a plurality of grooves  446 A formed in the at least one lateral surface  414 A of the superhard bearing element  408 A. The superhard bearing element  408 A also includes a plurality of exterior fins  448 A formed between the plurality of grooves  446 A. For example, each exterior fin  448 A may be formed by and between circumferentially adjacent grooves  446 A. The plurality of exterior fins  448 A may increase the surface area of the superhard bearing element  408 A to enhance heat transfer from the superhard bearing element  408 A to at least one environment about the superhard bearing element  408 A, a coolant fluid that flows around the superhard bearing element  408 A, or a support structure. 
     The grooves  446 A may be formed by electro-discharge machining, laser-cutting, computer numerical control (“CNC”) milling, grinding, combinations thereof, or otherwise machining the grooves  446 A in the superhard bearing element  408 A. For example, suitable laser-machining techniques are disclosed in U.S. Pat. No. 9,062,505 filed on Jun. 22, 2011, the disclosure of which is incorporated herein, in its entirety, by this reference. 
     In an embodiment, some or all of the grooves  446 A may follow a generally straight path (e.g., parallel to central axis  442 A) along the lateral surface  414 A with a length L that extends generally axially between the superhard sealing surface  410 A towards the base surface  412 A. In the illustrated embodiment, the length L of some or all of the grooves  446 A may extend along only a portion of the lateral surface  414 A. For example, the grooves  446 A may extend from or near the superhard sealing surface  410 A to a location above the base surface  412 A. the grooves  446 A may extend between the superhard sealing surface  410 A and the upper surface of the support structure. Such a configuration may help to secure the superhard bearing element  408 A to the support structure. For example, brazed-joint strength between the superhard bearing element  408 A and a recess of the support structure may be improved by providing a lateral surface on the portion of the superhard bearing element  408 A within the recess that generally corresponds to a lateral surface of the recess. In an embodiment (not shown), some or all of the grooves  446 A may be formed substantially parallel to the superhard sealing surface  410 A. 
     Moreover, while the grooves  446 A may follow a generally straight path, some or all of the grooves  446 A may follow a generally arcuate path, a generally semi-cylindrical path, a generally helical path, a generally S-shaped path, a generally U-shaped path, a generally V-shaped path, a generally linear path, or any other suitable path. The shape of the exterior fins  448 A may depend on the path of the grooves  446 A. For example, grooves  446 A exhibiting a generally arcuate path may form exterior fins  448 A exhibiting an arcuate shape. 
     As illustrated in  FIG. 4B , in an embodiment, the exterior fins  448 A extends inwardly from the lateral surface  414 A for a first distance and the superhard bearing element  408 A may include a chamfer  438 A that extends inwardly from the lateral surface  414 A for a second distance that is greater than or equal to the first distance. In such an embodiment, the chamfer  438 A may prevent chipping in the superhard bearing element  408 A because the chamfer  438 A prevents the exterior fins  448 A from contacting an opposing sealing surface during operation. 
     In an embodiment, the exterior fins  448 A may include edge features configured to influence flow conditions (e.g., influence flow of a gas or coolant fluid about the superhard bearing element  408 A). For example, the exterior fins  448 A may include beveled edges, rounded edges, chamfered edges, or the like. One or more of the exterior fins  448 A may include edges that are sharpened, have notches, irregularly shaped, combinations thereof, or the like. Such a configuration may allow the exterior fins  448 A to partially agitate, break-up or create desired flow characteristics in a coolant fluid (e.g., a gas or liquid) that is in contact with the superhard bearing element  408 A. Further, such edge features may also be selected to increase the surface area of the exterior fins  448 A. 
     In an embodiment, the grooves  446 A may have a generally U-shaped cross-section, a generally V-shaped cross-section, a generally rectangular cross-section, a generally semi-circular shaped cross-section, a generally parabolic shaped cross-section, a generally trapezoidal shaped cross-section, combinations thereof, or the like. The cross-section of the grooves  446 A may influence the flow conditions of a coolant gas or coolant liquid. For example, at least one of the grooves  446 A may have a portion including a U-shaped or V-shaped cross-section configured to improve cooling of the superhard bearing element  408 A by increasing the velocity/turbulence of a coolant fluid that contacts the superhard bearing element  408 A and/or increasing the surface area in contact with the coolant fluid. 
     In an embodiment, the exterior fins  448 A may be substantially equidistantly and circumferentially distributed about a central axis  442 A of the superhard bearing element  408 A. In such an embodiment, the grooves  446 A may be equidistantly and circumferentially distributed about the central axis  442 A of the superhard bearing element  408 A. In an embodiment, the exterior fins  448 A may be unevenly distributed about the periphery of the superhard bearing element  408 A. For example, the superhard bearing element  408 A may include one or more exterior fins  448 A on a first side of the lateral surface  414 A and no grooves on a second side of the lateral surface  414 A generally opposite the first side. 
       FIGS. 4C and 4D  are a side view and a top plan view, respectively, of a superhard bearing element  408 C shown with respect to a central axis  442 C, according to an embodiment. The superhard bearing element  408 C includes a lateral surface  414 C. The superhard bearing element  408 C includes a plurality of grooves  446 C formed in the lateral surface  414 C (e.g., substantially parallel to central axis  442 C). The grooves  446 C circumferentially separate adjacent exterior fins  448 C of a plurality of exterior fins  448 C. One or more features of the grooves  446 C and the exterior fins  448 C may be the same or similar to one or more features of the grooves  446 A and exterior fins  448 A of  FIGS. 4A-4B , respectively. As shown in  FIGS. 4C and 4D , expect that the grooves  446 C and the exterior fins  448 A extend from or near the superhard sealing surface  410 C to an base surface  412 C of the superhard bearing element  408 C. The grooves  446 C and the exterior fins  448 C may increase the total surface area of the superhard bearing element  408 C relative to the superhard bearing element  408 A of  FIGS. 4A-4B . The increased surface area of the superhard bearing element  408 C can increase the amount of heat that is transferred from superhard bearing element  408 C, such as increasing the amount of heat that is transferred from the superhard bearing element  408 C to a support structure. 
     In an embodiment, a support structure may configured to be coupled to the superhard bearing element  408 C via a recess exhibiting a shape that substantially corresponds to the shape of the superhard bearing element  408 C (e.g., the recess includes a plurality of protrusions that substantially correspond to the grooves  446 C). In an embodiment, the superhard bearing elements  408 C may be brazed to a support structure. 
       FIGS. 4E and 4F  are a side view and a top plan view, respectively, of a superhard bearing element  408 E shown with respect to a central axis  442 E, according to an embodiment. The superhard bearing element  408 E includes at least one lateral surface  414 E extending between a superhard sealing surface  410 E and a base surface  412 E of the superhard bearing element  408 E. The superhard bearing element  408 E also includes a plurality of exterior fins  448 E that are coupled (e.g., attached) to at least a portion of the lateral surface  414 E. The exterior fins  448 E may be circumferentially distributed about the superhard bearing element  408 E (e.g., about central axis  442 E). The exterior fins  448 E increase the surface area of the superhard bearing element  408 E that is exposed to at least one an environment about the superhard bearing element  408 E, a coolant fluid that flows around the superhard bearing element  408 E, or the support structure. As such, the exterior fins  448 E can increase an amount of heat that is transferred from the superhard bearing element  408 E into the environment, a coolant fluid, and/or a support structure. Further, the exterior fins  448 E can increase the velocity/turbulence of a coolant fluid flowing around the superhard bearing element  408 E and/or capture more of the coolant fluid flowing around the superhard bearing element  408 E, each of which can increase the amount of heat transferred into the coolant fluid. 
     In an embodiment, some or all of the exterior fins  448 E may extend from a first location at or near the superhard sealing surface  410 E to a second location above the base surface  412 E. In an embodiment, the second location may generally correspond to an upper surface of a support structure. Such a configuration may help to secure the superhard bearing element  408 E to the support structure. For example, brazed joint strength between the superhard bearing element  408 E and a recess of the support structure may be improved by providing a lateral surface  414 E on the portion of the superhard bearing element  408 E within the recess that generally corresponds to a lateral surface of the recess. In an embodiment (not shown), some or all of the exterior fins  448 E may be extend substantially parallel to the central axis  442 E. 
     In an embodiment, the first location of some or all of the exterior fins  448 E are below the superhard sealing surface  410 E. For example, the first location of some or all of the exterior fins  448 E is at or below an intersection of the lateral surface  414 E and a chamfer  438 E. In such an embodiment, the exterior fins  448 E do not contact and bear against an opposing bearing element during operation. As such, the exterior fins  448 E are less likely to be damaged during operation. In an embodiment, the first location of some or all of the exterior fins  448 E is at the superhard sealing surface  410 E. In such an embodiment, some or all of the exterior fins  448 E may contact and bear against an opposing bearing element during operation. To limit or inhibit damage of the exterior fins  448 E, an uppermost edge of the exterior fins  448 E (e.g., the edge that may contact and bear against an opposing bearing element) may be rounded or chamfered. 
     The exterior fins  448 E may exhibit any of a variety of configurations. For example, one or more of the exterior fins  448 E may have a generally rectangular shape, an arcuate shape, a generally crescent shape, a generally s-like shape, a generally u-like shape, a generally v-like shape, any other suitable shape, or combinations thereof. In an embodiment, one or more of the exterior fins  448 E may include surface features configure to increase the surface area of the exterior fins  448 E and/or direct a flow of a coolant fluid around the superhard bearing element  408 E. The surface features may include one or more of channels, textural surfaces, nubs, slots, through holes, divots, ridges, notches, any other suitable surface features, or combinations thereof. 
     In an embodiment, one or more of the exterior fins  448 E may include edge features configured to modify at least one of the surface area of the exterior fins  448 E or coolant fluid flow around the superhard bearing element  408 E. For example, one or more of the exterior fins  448 E may include edges that are rounded, flat, curved, combinations thereof, or other suitable edge features. In other embodiments, the exterior fins  448 E may include edges that are sharpened, notched, irregularly shaped, combinations thereof, or the like. Such a configuration may allow the exterior fins  448 E to partially agitate, direct, or create a desired flow characteristic in the coolant fluid. 
     The exterior fins  448 E may be formed in any suitable manner, and no particular method for forming the exterior fins  448 E is to be considered limiting. For example, the exterior fins  448 E may be formed of carbon steel, stainless steel, tungsten carbide, ceramic materials (e.g., cemented carbides, polycrystalline diamond), composites, other suitable materials, or combinations thereof. In an embodiment, the exterior fins  448 E may include PCD or may be substantially diamond free. In an embodiment, the exterior fins  448 E may be integrally or separately formed from the same material as the superhard bearing element  408 E. For example, the superhard bearing element  408 E may include a PCD table and the exterior fins  448 E may include PCD. Forming the exterior fins  448 E from PCD can increase the amount of heat that is transferred from the superhard bearing element  408 E due to the high thermal conductivity of PCD. In an embodiment, the exterior fins  448 E may be formed from a different material than the superhard bearing element  408 E. In an example, the exterior fins  448 E may be formed of a material exhibiting a higher thermal conductivity than the superhard bearing element  408 E. In an example, the exterior fins  448 E may be formed of a material that is cheaper and/or easily coupled to the superhard bearing element (e.g., the superhard bearing element  408 E includes a PCD table and the exterior fins  448 E includes cobalt-cemented tungsten carbide that is bonded to the PCD table). 
     In an embodiment, the exterior fins  448 E may be secured to the superhard bearing element  408 E via brazing, welding, press-fitting, fastening with one or more fasteners, an HPHT process, or any other suitable process. 
       FIGS. 4G and 4H  are a side view and a top plan view of a superhard bearing element  408 G shown with respect to a central axis  442 G, according to an embodiment. The superhard bearing element  408 G includes a lateral surface  414 G. The superhard bearing element  408 G includes a plurality of exterior fins  448 G coupled to the lateral surface  414 G. One or more features of the exterior fins  448 G may be the same or similar to at least one feature of the exterior fins  448 E of  FIGS. 4E-4F , respectively. In an embodiment, the exterior fins  448 E extend from a first location at or near the superhard sealing surface  410 G to an base surface  412 G of the superhard bearing element  408 G. The exterior fins  448 G may increase the total surface area of the superhard bearing element  408 G relative to the superhard bearing element  408 E of  FIGS. 4E-4F . The increased surface area of the superhard bearing element  408 G can increase the amount of heat that is transferred from superhard bearing element  408 G, such as increasing the amount of heat that is transferred from the superhard bearing element  408 G (e.g., support structure of a fluid). 
     In an embodiment, the support structure that is configured to be coupled to the superhard bearing element  408 G may define a recess exhibiting a shape that substantially corresponds to the shape of the superhard bearing element  408 G (e.g., the recess includes a plurality of channels that substantially correspond to the exterior fins  448 G). 
       FIGS. 4I and 4J  are a side cross-sectional view and a top plan view of a superhard bearing element  4081  as shown with respect to a central axis  4421 , according to an embodiment. The conduit  4161  of the superhard bearing element  4081  is defined by an interior surface  4201  of the superhard bearing element  4081 . The interior surface  4201  may include a plurality of grooves  4461  formed therein. The plurality of grooves  4461  may form a plurality of interior fins  4501  between adjacent grooves  4461 . At least one feature of the grooves  4461  and the interior fins  4501  may be the same or substantially similar to at least one feature of the groove  446 A and the exterior fins  448 A of  FIGS. 4A-4B , respectively. In an embodiment, the grooves  4461  and the interior fins  4501  are formed in the interior surface  4201  of the superhard bearing element  4081 . The superhard bearing element  4081  may also include a plurality of exterior fins  4481 , such as any of the exterior fins disclosed herein. 
     The grooves  4461  and the interior fins  4501  may increase the surface area of the superhard bearing element  408 E that is exposed to a fluid flowing through the conduit  416 . As such, the grooves  4461  and the interior fins  4501  can increase the amount of heat that is transferred into the fluid flowing through the conduit  4161 . 
     In an embodiment, the grooves  4461  and the interior fins  4501  extend from or near the superhard sealing surface  4101  to a first location that is spaced from a base surface  4121  of the superhard bearing element  4081 . For example, the heat is generated by the superhard bearing element  4081  at or near the superhard sealing surface  4101 . As such, the grooves  4461  and the interior fins  4501  may decrease the temperature of the superhard bearing element  4081 . 
       FIGS. 4K and 4L  are a side view and a top plan view of a superhard bearing element  408 K as shown with respect to a central axis  442 K, according to an embodiment. The conduit  416 K of the superhard bearing element  408 K is defined by an interior surface  420 K of the superhard bearing element  408 K. The interior surface  420 K may include a plurality of grooves  446 K formed therein. The plurality of grooves  446 K may form a plurality of interior fins  450 K between adjacent grooves  446 K. One or more features of the grooves  446 K or the interior fins  4501  may be the same or substantially similar to one or more features of the groove  446 C or the exterior fins  448 C of  FIGS. 4C-4D , respectively. In an embodiment, the grooves  446 K and the interior fins  450 K are formed in the interior surface  420 K of the superhard bearing element  408 K. The superhard bearing element  408 K may also include a plurality of exterior fins  448 K, such as any of the exterior fins disclosed herein. 
     In an embodiment, the grooves  446 K and the interior fins  450 K extend from or near the superhard sealing surface  410 K to a base surface  412 K of the superhard bearing element  408 K. As such, the grooves  446 K and the interior fins  450 K cause the superhard bearing element  408 K to exhibit a larger surface area that is exposed to a fluid flow therethrough than the superhard bearing element  4081  of  FIGS. 4I-4J . Therefore, the grooves  446 K and the interior fins  450 K can cause more heat to be transferred from the superhard bearing element  408 K than if the grooves  446 K and the interior fins  450 K only extend along a portion of the length of the interior surface  420 K. 
       FIGS. 4M and 4N  are a side view and a top plan view of a superhard bearing element  408 M shown with respect to a central axis  442 M, according to an embodiment. The superhard bearing element  408 M includes a conduit  416 M that is defined by an interior surface  420 M of the superhard bearing element  408 M. The interior surface  420 M may include a plurality of interior fins  450 M coupled thereto. One or more features of the interior fins  450 M may be the same or substantially similar to one or more features of the exterior fins  448 E of  FIGS. 4E-4F . In an embodiment, the interior fins  450 M are coupled to the interior surface  420 M of the superhard bearing element  408 M. The interior fins  450 M increase the surface area of the superhard bearing element  408 M that is exposed to a fluid flowing through the conduit  416 M. As such, the interior fins  450 M can increase the amount of heat that is transferred into the fluid flowing through the conduit  416 M. The superhard bearing element  408 M may also include a plurality of exterior fins  448 M, such as any of the exterior fins disclosed herein. 
     In an embodiment, the interior fins  450 M extend from or near the superhard sealing surface  410 M to a first location that is spaced from a base surface  412 M of the superhard bearing element  408 M. For example, the maximum temperatures generated by the superhard bearing element  408 M are at or near the superhard sealing surface  410 M. As such, the interior fins  450 M can decrease the maximum temperatures generated by the superhard bearing element  408 M. 
       FIGS. 4P and 4Q  are a side view and a top plan view of a superhard bearing element  408 P shown with respect to a central axis  442 P, according to an embodiment. The superhard bearing element  408 P includes a conduit  416 P that is defined by an interior surface  420 P of the superhard bearing element  408 P. The interior surface  420 P may include a plurality of interior fins  450 P coupled thereto. One or more features of the interior fins  450 P may be the same or substantially similar to one or more features of the exterior fins  448 G of  FIGS. 4G-41I . In an embodiment, the interior fins  450 P are coupled to the interior surface  420 P of the superhard bearing element  408 P. The superhard bearing element  408 P may also include a plurality of exterior fins  448 P, such as any of the exterior fins disclosed therein. 
     In an embodiment, the interior fins  450 P extend from or near the superhard sealing surface  410 P to a base surface  412 P of the superhard bearing element  408 P. As such, the interior fins  450 P may cause the superhard bearing element  408 P to exhibit a larger surface area that is exposed to a fluid flow therethrough (e.g., as compared to a similar-sized superhard bearing element  408 M of  FIGS. 4M-4N ). Therefore, the interior fins  450 P can cause more heat to be transferred from the superhard bearing element  408 P than if the interior fins  450 P only extend along a portion of the length of the interior surface  420 P. 
     Any of the above-described embodiments may be employed in a bearing apparatus.  FIG. 5  is a side cross-sectional view of a portion of a bearing apparatus  552 , according to any embodiment. The bearing apparatus  552  includes a bearing assembly  554  and bearing assembly  556 . The terms “rotor” and “stator” refer to rotating and stationary components of the bearing apparatus  552 , respectively. For example, the bearing assembly  554  may be the rotor and the bearing assembly  556  may be the stator, or vice versa. 
     In an embodiment, as illustrated, one or more features of the stator bearing assembly  554  is the same as or substantially similar to one or more features of any of the bearing assemblies disclosed herein. For example, the stator bearing assembly  554  may include a first support structure  502 A and a superhard bearing element  508 A. The first support structure  502 A and the first superhard bearing element  508 A may include any of the support structures or superhard bearing elements disclosed herein. For example, the superhard bearing element  508 A may include a first superhard sealing surface  510 A. The stator bearing assembly  554  may also define a first conduit  516  extending therethrough. 
     The first conduit  516  may include a first support structure conduit  516 A extending through the first support structure  502 A and a first bearing element conduit  516 B extending through the first superhard bearing element  508 A. 
     In an embodiment, as illustrated, one or more features of the bearing assembly  556  may be the same as or substantially similar to one or more features of any of the bearing assemblies disclosed herein. For example, the bearing assembly  556  may include a second support structure  502 B and a second superhard bearing element  508 B. The second support structure  502   b  and the second superhard bearing element  508 B may include any of the support structures or superhard bearing elements disclosed herein. For example, the second superhard bearing element  508 B may include a second superhard sealing surface  510 B. The bearing assembly  556  may also define a second conduit  558  extending therethrough. The second conduit  558  may include a second support structure conduit  558 A extending through the second support structure  502 B and a second bearing element conduit  558 B extending through the second superhard bearing element  508 B. 
     In an embodiment, the first superhard bearing element  508 A and the second superhard bearing element  508 B includes substantially the same materials. In such an embodiment, the first and second superhard bearing elements  508 A,  508 B wear at substantially the same rate. In an embodiment, the first superhard bearing element  508 A and the second superhard bearing element  508 B include different materials. For example, one of the first or second superhard bearing elements  508 A,  508 B may include a first superhard material and the other of the first or second superhard bearing elements  508 A,  508 B may include a second superhard material. The first superhard material may exhibit a wear resistance that is greater than the second superhard material. As such, the second superhard material may wear at a faster rate than the first superhard material which may cause the superhard bearing element that includes the second superhard material to better conform to the superhard bearing element that includes the first superhard material. Such a configuration may better inhibit the flow of the fluid between the first and second superhard sealing surfaces  510 A,  510 B. Additionally, preferentially wearing the superhard bearing element that includes the second superhard material may cause the superhard bearing element that includes the second superhard material to exhibit a relatively smooth or very smooth surface finish faster than if both superhard bearing elements included the first superhard material. In an embodiment, the superhard bearing element that includes the second superhard material can decrease the costs of operating the bearing apparatus  552 . For example, the first superhard material (e.g., PCD) can more expensive than the second superhard material (e.g., tungsten carbide). Preferentially wearing the superhard bearing element that includes the second superhard material relative to the superhard bearing element that includes the first superhard material may increase the life span of the more expensive superhard bearing element. 
     The bearing assembly  552  may optionally include a housing  560  defining a passage  562 . In an embodiment, passage  562  may be substantially scaled to form a chamber. The bearing assembly  554  and the bearing assembly  556  may be at least partially disposed in the passage  562 . In an embodiment, the passage  562  is not sealed. The housing  560  may be configured to be stationary or rotate relative to at least the bearing assembly  554 . In an embodiment, the housing  560  does not include one or more O-rings or other sealing devices because the bearing assembly  554  and the bearing assembly  556  may be configured to prevent the fluid flowing through the first and second conduits  516 ,  558  from leaking into the passage  562 . 
     The bearing assembly  554  and the bearing assembly  556  are positioned such that the first and the second superhard sealing surfaces  510 A,  510 B contact each other and the first and second conduits  516 ,  558  are aligned with one another. In operation, the bearing assembly  556  may rotate relative to the bearing assembly  554  and a fluid may flow through the first and second conduits  516 ,  558 . In an embodiment, the fluid may flow through the first and second conduit  516 ,  558  substantially without leaking between the first and second superhard sealing surfaces  510 A,  510 B. 
     However, in operation, the first and second superhard bearing elements  508 A,  508 B can generate significant amounts of heat. As such, in operation, at least one of the bearing assembly  554  or the bearing assembly  556  may be configured to transfer heat from the superhard bearing elements thereof. In an embodiment, at least one of the first or second superhard bearing elements  508 A,  508 B may be configured to transfer heat into the first or second support structure  502 A,  502 B. 
     In an embodiment, at least one of the first or second superhard bearing elements  508 A,  508 B may be configured to transfer heat into the passage  562  (e.g., into the atmosphere about the first or second superhard bearing elements  508 A,  508 B). For example, any surface of the superhard bearing elements  508 A,  508 B that are exposed to the passage  562  can transfer heat into the passage  562 . However, transferring heat into the passage  562  into the passage  562  may be inefficient because the passage  562  may be filled with a gas (e.g., air) and the gas may be stationary. As such, at least one of the first or second superhard bearing elements  508 A,  508 B may include exterior fins. The exterior fins may increase the surface area of the superhard bearing elements  508 A,  508 B thereby increasing the amount of heat that is transferred into the passage  562 . Further, the exterior fins may cause the gas in the passage  562  to move thereby increasing the amount of heat that is transferred into the passage  562 . 
     In an embodiment, at least one of the first or second superhard bearing elements  508 A,  508 B may be configured to transfer heat into the fluid flowing through the first and second conduits  516 ,  558 . The amount of heat that is transferred into the fluid may depend directly on the surface area of the first or second superhard bearing elements  508 A,  508 B that contact the fluid. For example, at least one of the first or second superhard bearing elements  508 A,  508 B may include a plurality of interior fins. In an embodiment, the fluid flow through the first or second conduits  516 ,  558  may be intermittent, which can limit the amount of heat that is transferred into the fluid. However, the presence of the interior fins can enhance the amount of heat that is transferred into the fluid when it does flow through the first and second conduits  516 ,  558  and can increase the amount of heat that is transferred into the first and second conduits  516 ,  558  when the fluid is not flowing through the first and second conduits  516 ,  558  (e.g., transfers heat into a stagnant fluid). Further, the presence of other thermal management features can limit the temperature of and/or limit damage to the first and second superhard bearing elements  508 A,  508 B when the fluid is not flowing the first and second conduits  516 ,  558 . Temperature of one of the rotor and/or stator may be measured. In an embodiment, fluid flow may be increased when the temperature exceeds a selected value. 
     It is noted that, in an embodiment, one of the bearing assembly  554  or the bearing assembly  556  may be different than the bearing assemblies disclosed herein. In an example, one of the bearing assembly  554  or the bearing assembly  556  may include a non-superhard bearing element defining a conduit instead of the superhard bearing element. In an example, one of the bearing assembly  554  or the bearing assembly  556  may include a single component defining a conduit that functions as both a bearing element and a support structure. 
       FIG. 6  is a side cross-sectional view of a portion of a bearing apparatus  652 , according to any embodiment. In an embodiment, at least one feature of the bearing apparatus  652  may be the same as or substantially similar to at least one feature of the bearing apparatus  552  of  FIG. 5 . For example, the bearing apparatus  652  may include a bearing assembly  654  including a first superhard bearing element  608 A, a bearing assembly  656  including a second superhard bearing element  608 B, and a housing  660  defining a passage  662 . At least a portion of the bearing assembly  654  and the bearing assembly  656  are disposed in the passage  662 . 
     The housing  660  may define an inlet  664  and an outlet  668 . The bearing apparatus  652  may also include a coolant source  670  (e.g., a pump) coupled to the inlet  664 . For example, the bearing apparatus  652  may include tubing  671  extending from the coolant source  670  to the inlet  664 . The coolant source  670  may include a coolant fluid disposed therein or may be configured to draw coolant fluid from a reservoir. The coolant source  670  may be configured to flow the coolant fluid into the passage  662 . 
     The coolant fluid may be dispelled from the passage  662  using the outlet  668 . Optionally, coolant fluid dispelled from passage  662  may be recirculated via coolant source  664 . As such, the coolant fluid may flow around at least a portion of the first superhard bearing element  608 A and/or second superhard bearing elements  608 B, thereby increasing the amount of heat transferred from the first superhard bearing element  608 A and/or second superhard bearing elements  608 A,  608 B (e.g., a gas, a liquid, or both). 
     The coolant fluid may include any fluid. In an example, the coolant fluid may include a fluid that exhibits room temperature (e.g., about 20° C. to about 30° C.). In an example, the coolant fluid may include a fluid that exhibits a temperature that is greater than about room temperature. In an embodiment, the coolant fluid may include a fluid that exhibits a temperature that is less than room temperature, such as when the coolant source  670  includes a chiller. Cooling the coolant fluid to a temperature that is less than room temperature may increase the amount of heat transferred from the first and second superhard bearing elements  608 A,  608 B to the coolant fluid. In an embodiment, the coolant source  670  may be coupled to the outlet  668  such that the coolant source  670  receives the coolant fluid that was dispelled from the passage  662  and recirculates the coolant fluid. In an embodiment, the coolant fluid includes a liquid. In such an embodiment, O-rings or other sealing devices may be configured to fluidly seal the passage  662 . In an example, the coolant fluid includes a gas, such as atmospheric air or nitrogen. In an embodiment, a gaseous coolant fluid may not include O-rings or other sealing device (e.g., since the gaseous coolant fluid may be dispensed into the atmosphere). Also, a gaseous coolant fluid may contact the first and second superhard bearing elements  608 A,  608 B without exhibiting a phase change due to the heat absorbed thereby, unlike some liquid coolant fluids. Accordingly, any gas, fluid, or mixture of gas and fluid may be employed to achieve a desired heat transfer or cooling, without limitation. 
     In an embodiment, at least one of the superhard bearing elements, bearing assemblies, or bearing apparatus may include two or more conduits. In an example, the two or more conduits may be configured to allow two or more different fluids to flow therethrough (e.g., the two or more fluids flowing in the same direction). In an example, the two or more conduits may be configured to have the same fluid to flow therethrough. For example, one of the two or more conduits may form a fluid intake while another of the two or more conduits may form a fluid exhaust. 
       FIGS. 7A and 7B  are a schematic cross-sectional view and a top plan view, respectively, of a bearing assembly  700 , according to an embodiment. In an embodiment, at least one feature of the bearing assembly  700  may be the same as or similar to at least one feature of any of the bearing assemblies disclosed herein. For example, the bearing assembly  700  may include a support structure  702  and a superhard bearing element  708  that, except as otherwise disclosed herein, are the same as or substantially similar to any of the support structures and superhard bearing elements disclosed herein. Optionally, bearing assembly  700  may be used in any of the bearing apparatuses disclosed herein. 
     The bearing assembly  700  defines a first conduit  716  and a second conduit  772  extending therethrough, respectively. The first conduit  716  may include a conduit section  716 A extending through the support structure  702  and a conduit section  716 B extending through the superhard bearing element  708 . The first conduit  716  may also include a first port  774 A where the first conduit  716  opens to the superhard sealing surface  710 . In an embodiment, the first port  774 A is located at a center of the superhard sealing surface  710 . In such an embodiment, the first port  774 A may remain substantially fluidly coupled with a corresponding conduit of an opposing bearing element (e.g., the corresponding conduit of the opposing bearing element includes a port at a center of the sealing surface thereof). In an embodiment, the first port  774 A may be spaced from the center of the superhard sealing surface  710 . In such an embodiment, the first port  774 A may be aligned with an identical corresponding conduit occasionally during rotation. 
     The second conduit  772  may include a second support structure conduit  716 A extending through the support structure  772 A and a second bearing element conduit  772 B extending through the superhard bearing element  708 . The second conduit  772  may also include a second port  774 B where the second conduit  772  extends to the superhard sealing surface  710 . The second port  774 B is located radially outwardly from the first port  774 A. As such, the second portion  774 B may be intermittently aligned with to a corresponding conduit of an identical, opposing bearing element during rotation. 
       FIGS. 8A and 8B  are a schematic cross-sectional view and a top plan view, respectively, of a bearing assembly  800 , according to an embodiment. In an embodiment, at least one feature of the bearing assembly  800  may be the same as or substantially similar to at least one feature of any of the bearing assemblies disclosed herein. For example, the bearing assembly  800  may include a support structure  802  and a superhard bearing element  808  that, except as otherwise disclosed herein, are the same as or substantially similar to any of the support structures or superhard bearing elements disclosed herein, respectively. Further, the bearing assembly  800  may be used in any of the bearing apparatuses disclosed herein. 
     The bearing assembly  800  includes a first conduit  816  and a second conduit  872  extending therethrough. At least one feature of the first and second conduits  816 ,  872  may be the same as or substantially similar to at least one feature of the first and second conduits  716 ,  772  of  FIGS. 7A-7B . For example, the first conduit  816 A may include a first port  874 A located at a center of the superhard sealing surface  810  and the second conduit  872  may include a second port  874 B spaced from the center of the superhard sealing surface  810 . The bearing assembly  800  also includes at least one channel  886  formed in the superhard bearing element  808 . The channel  886  may be spaced from a center of the superhard sealing surface  810  by a selected distance that corresponds to a location of the second port  874 B of second conduit  872 . The channel  886  may allow the second portion  874 B to be continuously coupled (e.g., during rotation allowing fluid to flow between the conduits  772 ,  872 ) to a corresponding conduit of an opposing bearing element configured as bearing assembly  700  or an identical opposing bearing element  800 . For example, the opposing bearing element can flow fluid directly into the second portion  874 B when the conduit  772 ,  872  of the opposing bearing element  708 ,  808  is rotating (e.g., the conduit  772 ,  872  of the opposing bearing element  708 ,  808  may conduct fluid into the channel  886  of the first bearing element  808  and the fluid may flow through the channel  886  until it reaches the second portion  874 B). 
       FIG. 9  is a schematic cross-sectional view of a bearing apparatus  952 , according to an embodiment. In an embodiment, at least one feature of the bearing apparatus  952  may be the same as or substantially similar to at least one feature any of the bearing apparatuses disclosed herein. For example, the bearing apparatus  952  may include a bearing assembly  954  and a bearing assembly  956 . At least one feature of the bearing assembly  954  may be the same as or substantially to similar to at least one feature of the bearing assembly  700  of  FIGS. 7A-7B  or the bearing assembly  800  of  FIGS. 8A-8B . At least one feature of the bearing assembly  956  may be the same as or substantially similar to at least one feature of the bearing assembly  700  of  FIGS. 7A-7B  or the bearing assembly  800  of  FIGS. 8A-8B . In an embodiment, bearing assembly  954  may be a stator and bearing assembly  956  may be a stator, or vice versa. 
     In an embodiment, the bearing assembly  954  may include a first conduit  916 A and a second conduit  972 A and the bearing assembly  956  may include a third conduit  916 B and a fourth conduit  972 B. The first conduit  916 A and the third conduit  916 B may be coupled together (to conduct fluid therethrough, collectively) and the second conduit  972 A and the fourth conduit  972 B may be coupled together (to conduct fluid therethrough, collectively). In an embodiment, the first and third conduits  916 A,  916 B may continuously conduct fluid because the ports of the first and third conduits  916 A,  916 B are located at a center of their respective superhard sealing surfaces  910 A,  910 B even when one of the bearing assemblies  954 ,  956  is rotating relative to the other of the bearing assemblies  954 ,  956 . In an embodiment, the second and fourth conduits  972 A,  972 B may continuously conduct fluid even when one of the bearing assemblies  854 ,  956  is rotating relative to the other of the bearing assemblies  954 ,  956  because the bearing assembly  954  includes a channel  976  that corresponds to the ports of the second and fourth conduits  972 A,  972 B. It is noted that the bearing assembly  956  may include a channel instead of or in conjunction with the bearing assembly  954 . 
       FIG. 10  is a schematic cross-sectional view of a bearing apparatus  1052 , according to an embodiment. In an embodiment, at least one feature of the bearing apparatus  1052  may be the same as or substantially similar to at least one feature of any of the bearing apparatuses disclosed herein. For example, the bearing apparatus  1052  may include a first bearing assembly  1054  including a first superhard bearing element  1008 A, a second bearing assembly  1056  including a second superhard bearing element  1008 B coupled to a support structure  1002 , and a housing  1060  defining a passage  1062  that includes at least a portion of the first bearing assembly  1054  and the second bearing assembly  1056  disposed therein. The first bearing assembly  1054  may form the stator or rotor of the bearing apparatus  1052  and the second bearing assembly  1056  may form the other of the stator or the rotor. 
     In an embodiment, the second bearing assembly  1056  may be configured to receive a fluid from the first bearing assembly  1054 . For example, the first bearing assembly  1054  defines at least one first conduit  1016 A extending therethrough and the second bearing assembly  1056  defines at least one second conduit  1016  extending therethrough. The first and second conduits  1016 A,  1016 B may be coupled together so as to flow a fluid therethrough. 
     In an embodiment, the second bearing assembly  1056  may be configured to also receive a fluid from (or through) the housing  1060 . For example, the housing  1060  may include a radial bearing assembly  1078 . The radial bearing assembly  1078  may include a bearing surface  1079  is configured to contact a lateral surface  1014  of the second superhard bearing element  1008 B. The radial bearing assembly  1078  may include a superhard material defining a bearing surface  1079  thereof (e.g., the bearing surface  1079  is a superhard bearing surface) or a non-superhard material defining the bearing surface  1079 . The radial bearing assembly  1078  may be coupled to or integrally formed with a body  1080  of the housing  1060 . The housing  1060  may define a third conduit  1082 . The third conduit  1082  may include a body conduit  1082 A extending through the body  1080  of the housing  1060  and a radial bearing element conduit  1082 B extending through the radial bearing assembly  1078 . 
     The second bearing assembly  1056  defines a fourth conduit  1072  extending therethrough. The fourth conduit  1072  may include a support structure conduit  1072 A extending through the support structure  1002  and a bearing element conduit  1072 B extending through the second superhard bearing element  1008 B. The bearing element conduit  1072 B may be configured (e.g., include a bend formed therein) to allow the fourth conduit  1072  to flow fluid to a port  1074  on a lateral surface  1014  of the second superhard bearing element  1008 B. As such, the fourth conduit  1072  may conduct fluid to or from the third conduit  1082 . 
     In an embodiment, the radial bearing assembly  1078  defines a channel  1076  therein that allows the third conduit  1082  to be continuously coupled to the fourth conduit  1072 . In an embodiment, the second superhard bearing element  1008 B defines a channel (not shown) that continuously allows fluid to pass between the fourth conduit  1072  and the third conduit  1082 . In such an embodiment, the radial bearing assembly  1078  may define the channel  1076  or the channel  1076  may be omitted therefrom. In an embodiment, neither the radial bearing assembly  1078  or the second superhard bearing element  1008 B defines a channel. 
       FIG. 11  is a schematic cross-sectional view of a bearing apparatus  1152 , according to an embodiment. In an embodiment, at least one feature of the bearing apparatus  1152  may be the same as or substantially similar to at least one feature of any of the bearing apparatuses disclosed herein. For example, the bearing apparatus  1152  may include a first bearing assembly  1154  including a first superhard bearing element  1108 A, a second bearing assembly  1156  including a second superhard bearing element  1108 B coupled to a support structure  1102 , and a housing  1160  defining a passage  1162  that includes at least a portion of the first bearing assembly  1154  and the second bearing assembly  1156  disposed therein. The first bearing assembly  1154  may form the stator or rotor of the bearing apparatus  1152  and the second bearing assembly  1156  may form the other of the stator or the rotor. 
     In an embodiment, the second bearing assembly  1156  may be configured to receive a fluid from the first bearing assembly  1154 . For example, the first bearing assembly  1154  defines at least one first conduit  1116 A extending therethrough and the second bearing assembly  1156  defines at least one second conduit  1116 B extending therethrough. The first and second conduits  1116 A,  1116 B may be configured to flow fluid therethrough. 
     In an embodiment, the second bearing assembly  1156  may be configured to receive a fluid from the housing  1160 . For example, the housing  1160  may include a radial bearing assembly  1178 . The radial bearing assembly  1178  may include a bearing surface  1179  that is configured to contact and bear against a lateral surface  1184  of the support structure  1102 . The radial bearing assembly  1178  may include a superhard material defining a bearing surface  1179  thereof (e.g., the bearing surface  1179  is a superhard bearing surface) or a non-superhard material defining the bearing surface  1179 . The radial bearing assembly  1178  may be coupled to or integrally formed with a body  1180  of the housing  1160 . The housing  1160  may define a third conduit  1182 . The third conduit  1182  may include a body conduit  1182 A extending through the body  1180  of the housing  1160  and a radial bearing element conduit  1182 B extending through the radial bearing assembly  1178 . 
     The second bearing assembly  1156  defines a fourth conduit  1172  extending through the support structure  1102 . The fourth conduit  1172  may include a bend formed therein which allows the fourth conduit  1172  to include a port  1174  on the lateral surface  1184  of the support structure  1102 . As such, the fourth conduit  1172  and the third conduit  1182  may be configured to conduct fluid. In an embodiment, the portion of the lateral surface  1184  of the support structure  1102  that contacts the sealing surface  1179  may include a superhard material (e.g., the portion of the lateral surface  1184  is a superhard sealing surface). In an embodiment, the portion of the lateral surface  1184  of the support structure  1102  that contacts the sealing surface  1179  may include a non-superhard material. 
       FIG. 12  is a side cross-sectional view of a portion of a bearing apparatus  1252 , according to an embodiment. In an embodiment, at least one feature of the bearing apparatus  1252  may be the same as or substantially similar to at least one feature of any of the bearing apparatuses  1252  disclosed herein. For example, the bearing apparatus  1252  may include a bearing assembly  1254  including a first superhard bearing element  1208 A, a bearing assembly  1256  including a second superhard bearing element  1208 B, and a housing  1260  defining a passage  1262 . At least a portion of the bearing assembly  1254  and the bearing assembly  1256  are disposed in the passage  1262 . 
     The bearing assemblies  1254 ,  1256  may include a first support structure  1202 A and a second support structure  1202 B, respectively. Each of the first and second support structures  1202 A,  1202 B may include at least one support structure interior surface  1218  and at least one support structure exterior surface  1288 . The support structure interior surfaces  1218  of the first and second support structures  1202 A,  1202 B may at least partially define the conduits  1216 A,  1216 B of the first and second support structures  1202 A,  1202 B, respectively. The at least one support structure exterior surface  1288  may generally oppose the support structure interior surface  1218  and may at least partially define the passage  1262 . 
     In an embodiment, at least one of the first or second support structure  1202 A,  1202 B can include a plurality of fins separated from each other by a plurality of grooves formed therein. In an embodiment, at least one of the exterior surface  1288  of the first support structure  1202 A or the exterior surface  1288  of the second support structure  1202 B may include a plurality of exterior fins  1248 . At least one feature of the exterior fins  1248  may be the same as or substantially similar to any of the exterior fins disclosed herein. In an embodiment, at least one of the interior surface  1218  of the first support structure  1202 A or the interior surface of the second support structure  1202 B can include a plurality of interior fins  1250 . At least one feature of the plurality of interior fins  1250  can be the same as or substantially similar to at least one feature of any of the interior fins disclosed herein. In an embodiment, as shown, at least one of the exterior fins  1248  or the interior fins  1250  can extend in a circumferential direction. In an embodiment, at least one of the exterior fins  1248  or the interior fins  1250  can extend in an axial direction. 
     The exterior fins  1248  and/or the interior fins  1250  may facilitate heat removal from the first and second support structures  1202 A,  1202 B. For example, the first and second superhard bearing elements  1208 A,  1208 B may transfer heat to the first and second support structures  1202 A,  1202 B, respectively. The heat transferred into the first and second support structures  1202 A,  1202 B, if not dissipated, may damage the first and second support structures  1202 A,  1202 B and/or prevent the first and second superhard bearing elements  1208 A,  1208 B from transferring heat into the first and second support structures  1202 A,  1202 B. The exterior fins  1248  and/or the interior fins  1250  may increase heat dissipation from the first and second support structures  1202 A,  1202 B during operation thereby at least one of limiting damage to the first and second support structures  1202 A,  1202 B or increasing the heat transferred from the first and second superhard bearing elements  1208 A,  1208 B into the first and second support structures  1202 A,  1202 B, respectively. 
     While various aspects and embodiments have been disclosed herein, other aspects and embodiments are contemplated. The various aspects and embodiment disclosed herein are for purposes of illustration and are not intended to be limiting. Additionally, the words “including,” having,” and variants thereof (e.g., “includes” and “has”) as used herein, including the claims, shall be open ended and have the same meaning as the word “comprising” and variants thereof (e.g., “comprise” and “comprises”).