Patent Publication Number: US-11662149-B2

Title: Layered diffuser channel heat exchanger

Description:
FIELD 
     The present disclosure relates to heat exchangers, and, more particularly, to layered diffuser-channel heat exchanger assemblies and methods of forming the same. 
     BACKGROUND 
     Many aerospace applications, such as aircraft cabin cooling systems and/or aircraft refrigeration systems, employ heat exchangers to remove heat from an airflow. The airflow may flow through one or more heat exchanger channels during the heat exchange process. Fluid pressure drop through the channels of the heat exchanger should be carefully managed to minimize pressure losses. Further, many heat exchanger systems include an external fan to drive airflow and increase the heat transfer coefficient at the interface between air and the walls of the heat exchanger channels. External fans tend to increase the power demands and overall footprint of the heat exchanger. 
     SUMMARY 
     A layered diffuser-channel heat exchanger is disclosed herein. In accordance with various embodiments, the layered diffuser-channel heat exchanger may comprise a plurality of fluid channel layers and a plurality of diffuser fin layers interleaved with the plurality of fluid channel layers. Each fluid channel layer of the plurality of fluid channel layers may have a first surface, a second surface opposite the first surface, and a fluid channel located between the first surface and the second surface. 
     In various embodiments, a blower may be located in a central cavity surrounded by the plurality of fluid channel layers and the plurality of diffuser fin layers. In various embodiments, the blower may include a first stage of blades configured to rotate about an axis, a second stage of the blades configured to rotate about the axis, and a first stage of stationary vanes located axially between the first stage of blades and the second stage of the blades. The first stage of stationary vanes is configured to direct airflow between the first surface of a first fluid channel layer and the second surface of a second fluid channel layer. The plurality of fluid channels layer includes the first fluid channel layer and the second fluid channel layer. The first fluid channel layer is axially adjacent to the second fluid channel layer. 
     In various embodiments, the blower may further include a third stage of the blades configured to rotate about the axis, and a second stage of stationary vanes located axially between the second stage of blades and the third stage of the blades. The second stage of stationary vanes is configured to direct airflow between the first surface of the second fluid channel layer and the second surface of a third fluid channel layer. The plurality of fluid channels layer includes the third fluid channel layer. 
     In various embodiments, a motor may be located axially between the third stage of blades and the second stage of blades. In various embodiments, the first surface of a first fluid channel layer of the plurality of fluid channel layers is oriented at a non-perpendicular angle relative to an axis of rotation of the blower. 
     In various embodiments, a first diffuser fin layer of the plurality of diffuser fin layers includes a plurality of diffuser fins integrally formed with the first surface of a first fluid channel layer and the second surface of a second fluid channel layer. The plurality of fluid channel layers includes the first fluid channel layer and the second fluid channel layer. 
     In various embodiments, the plurality of diffuser fins includes a first group of diffuser fins having a first radial length, a second group of diffuser fins having a second radial length greater than the first radial length, and a third group of diffuser fins have a third radial length greater the second radial length. Each of the first group of diffuser fins, the second group of diffuser fins, and the third group of diffuser fins extends radially inward from an outer circumference of the first fluid channel layer. The third group may extend from the outer circumference of the first fluid channel layer to an inner circumference of the first fluid channel layer. 
     A method of making a layered diffuser-channel heat exchanger is also disclosed herein. In accordance with various embodiments, the method may comprise forming a first fluid channel layer having a first fluid channel located between a first surface and a second surface of the first fluid channel layer, forming a plurality of first diffuser fins extending from the first surface of the first fluid channel layer, and forming a second fluid channel layer over the plurality of first diffuser fins. The second fluid channel layer may have a second fluid channel located between a topside surface and an underside surface of the second fluid channel layer, the underside surface being integrally formed with the plurality of first diffuser fins. The method may further comprise forming a plurality of second diffuser fins extending from the topside surface of the second fluid channel layer. 
     In various embodiments, the first fluid channel layer, the plurality of first diffuser fins, the second fluid channel layer, and the plurality of second diffuser fins are formed using additive manufacturing. In various embodiments, the method may further comprise locating a blower in a central cavity surrounded by the first fluid channel layer, the plurality of first diffuser fins, the second fluid channel layer, and plurality of second diffuser fins. 
     In various embodiments, the method may further comprise locating a first stage of stationary vanes axially between a first stage of blades of the blower and a second stage of blades of the blower. The first stage of stationary vanes may be configured to direct airflow between the first surface of a first fluid channel layer and the underside surface of a second fluid channel layer. 
     In various embodiments, the method may further comprise orienting the first surface of the first fluid channel at a first non-perpendicular angle relative to an axis of rotation of first stage of blades of the blower, and orienting the topside surface of the second fluid channel at a second non-perpendicular angle relative to the axis of rotation of first stage of blades of the blower. 
     In various embodiments, the underside surface of the second fluid channel layer is integrally formed with the plurality of first diffuser fins. 
     In various embodiments, forming the plurality of first diffuser fins comprises forming a first group of the first diffuser fins having a first radial length, forming a second group of the first diffuser fins having a second radial length greater than the first radial length, and forming a third group of diffuser fins have a third radial length greater the second radial length. Each of the first group of first diffuser fins, the second group of first diffuser fins, and the third group of first diffuser fins extends radially inward from an outer circumference of the first fluid channel layer. 
     In various embodiments, the method further comprises locating a blower in a central cavity surrounded by the first fluid channel layer, the plurality of first diffuser fins, and the second fluid channel layer. The blower comprises a motor configured to drive rotation of a first stage of blades and a second stage of blades. The motor is located axially between the first stage of blades and the second stage of blades. 
     In accordance with various embodiments, a layered diffuser-channel heat exchanger may comprise a first fluid channel layer having a first fluid channel located between a first surface and a second surface of the first fluid channel layer, a plurality of first diffuser fins extending from the first surface of the first fluid channel layer, and a plurality of second diffuser fins extending from the second surface of the first fluid channel layer. The plurality of first diffuser fins is integrally formed with the first surface. The plurality of second diffuser fins is integrally formed with the second surface. 
     In various embodiments, the first fluid channel may be formed in a circumferential serpentine pattern. In various embodiments, a fluid source may be coupled to an inlet of first fluid channel. The circumferential serpentine pattern may cause the fluid from the first fluid source to flow circumferentially and radially inward across the first fluid channel layer. 
     In various embodiments, a second fluid channel layer may be integrally formed with the plurality of first diffuser fins. 
     The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated herein otherwise. These features and elements as well as the operation of the disclosed embodiments will become more apparent in light of the following description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures, wherein like numerals denote like elements. 
         FIG.  1 A  illustrates a perspective view of a layered diffuser-channel heat exchanger, in accordance with various embodiments; 
         FIG.  1 B  illustrates a cross-section view of the layered diffuser-channel heat exchanger of  FIG.  1 A , taken along the line  1 B- 1 B in  FIG.  1 A , in accordance with various embodiments; 
         FIGS.  2 A and  2 B  illustrate an exemplary cooling channel pattern for a layered diffuser-channel heat exchanger, in accordance with various embodiments; 
         FIG.  3    illustrates a portion of a diffuser fins layer for a layered diffuser-channel heat exchanger, in accordance with various embodiments; 
         FIG.  4    illustrates a layered diffuser-channel heat exchanger having a central motor, in accordance with various embodiments; 
         FIG.  5    illustrates a cross-section view of a layered diffuser-channel heat exchanger having vane stages between the cooling channel layers, in accordance with various embodiments; 
         FIG.  6    illustrates a cross-section view of a layered diffuser-channel heat exchanger having angled diffuser fins and fluid channel layers, in accordance with various embodiments; and 
         FIG.  7    illustrates a method of making a layered diffuser-channel heat exchanger, in accordance with various embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description of various embodiments herein makes reference to the accompanying drawings, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the inventions, it should be understood that other embodiments may be realized and that logical, mechanical changes may be made without departing from the spirit and scope of the inventions. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact. 
     Surface shading and/or cross-hatching lines may be used throughout the figures to denote different parts, but not necessarily to denote the same or different materials. Throughout the present disclosure, like reference numbers denote like elements. Accordingly, elements with like element numbering may be shown in the figures, but may not necessarily be repeated herein for the sake of clarity. 
     As used herein, the term “additive manufacturing” encompasses any method or process whereby a three-dimensional object is produced by creation of a substrate or material, such as by addition of successive layers of a material to an object to produce a manufactured product that has an increased mass or bulk at the end of the additive manufacturing process as compared to the beginning of the process. In contrast, traditional (i.e., non-additive) manufacturing by machining or tooling typically relies on material removal or subtractive processes, such as cutting, machining, extruding, lathing, drilling, grinding, stamping, and/or the like, to produce a final manufactured object that has a decreased mass or bulk relative to the starting workpiece. Other traditional, non-additive manufacturing methods include forging or casting, such as investment casting, which utilizes the steps of creating a form, making a mold of the form, and casting or forging a material (such as metal) using the mold. As used herein, the term “additive manufacturing” should not be construed to encompass a joining of previously formed objects. 
     A variety of additive manufacturing technologies are commercially available. Such technologies include, for example, fused deposition modeling, polyjet 3D printing, electron beam freeform fabrication, direct metal laser sintering, electron-beam melting, selective laser melting, selective heat sintering, selective laser sintering, stereolithography, multiphoton photopolymerization, and digital light processing. These technologies may use a variety of materials as substrates for an additive manufacturing process, including various plastics and polymers, metals and metal alloys, ceramic materials, metal clays, organic materials, and the like. Any method of additive manufacturing and associated compatible materials, whether presently available or yet to be developed, are intended to be included within the scope of the present disclosure. 
     Referring to  FIGS.  1 A and  1 B , a layered diffuser-channel heat exchanger  100  is illustrated. In accordance with various embodiments, layered diffuser-channel heat exchanger  100  includes alternating diffuser fins layers  102  and fluid channel layers  104 . For example, a first fluid channel layer  104   a  forms a base, or bottom, layer of layered diffuser-channel heat exchanger  100 . A first diffuser fins layer  102   a  is formed over first fluid channel layer  104   a . A second fluid channel layer  104   b  is formed over the first diffuser fins layer  102   a . A second diffuser fins layer  102   b  is formed over the second fluid channel layer  104   b . A third fluid channel layer  104   c  is formed over the second diffuser fins layer  102   b . A third diffuser fins layer  102   c  is formed over the third fluid channel layer  104   c . A fourth fluid channel layer  104   d  is formed over the third diffuser fins layer  102   c . A fourth diffuser fins layer  102   d  is formed over the fourth fluid channel layer  104   d , and so on. While layered diffuser-channel heat exchanger  100  is illustrated as having four (4) diffuser fins layers  102  and four (4) fluid channel layers  104 , it is contemplated and understood that layered diffuser-channel heat exchanger  100  may include any number of diffuser fins layers  102  and fluid channel layers  104 . 
     Each fluid channel layer  104  has a topside (or first) surface  106  and an underside (or second) surface  108 . Underside surface  108  is opposite (i.e., oriented away) from the topside surface  106 . One or more fluid channels  110  be located between the topside surface  106  and the underside surface  108  of each fluid channel layers  104 . Stated differently, each fluid channel layer  104  defines fluid channel(s)  110 . Fluid channels  110  may include a fluid inlet  112  and a fluid outlet  114 . In various embodiments, fluid inlet  112  and fluid outlet  114  are located at an outer circumference, or outer perimeter,  116  of the fluid channel layer  104 . 
     With reference to  FIGS.  2 A and  2 B , in various embodiments, fluid channels  110  may be formed in a circumferential serpentine pattern. In various embodiments, the fluid inlet  112  is coupled to the radially outward end of the serpentine pattern, and the fluid outlet  114  is coupled to the radially inward end of the serpentine pattern. In this regard, fluid flows radially inward as it flows circumferentially through serpentine pattern. In accordance with various embodiments, fluid from a fluid source may flow into fluid channel  110  via fluid inlet  112 . The fluid then begins flowing in a first circumferential direction C 1  through the fluid channel layer  104 . Fluid channels  110  may include one or more turns  118  configured to turn the fluid flow direction approximately 180°, such that at a turn  118  the fluid goes from flowing in the first circumferential direction C 1  to flowing in a second, opposite circumferential direction C 2 . As the fluid flows toward fluid outlet  114 , it may travel from proximate outer circumference  116  to proximate an inner circumference, or inner perimeter,  124  of the fluid channel layer  104 . Flowing fluid radially inward tends to locate the downstream portions of fluid channels  110  proximate the hotter areas of the of diffuser fins layer  102 , which may improve heat transfer capacity and/or thermal efficiency of layered diffuser-channel heat exchanger  100 . While fluid channel layer  104  is illustrated with fluid channel(s)  110  formed in a circumferential serpentine pattern, it is contemplated and understood that fluid channel layer  104  may include fluid channels  110  formed in other suitable geometries. 
     Returning to  FIGS.  1 A and  1 B , in accordance with various embodiments, each diffuser fins layer  102  includes a plurality of diffuser fins  120  extend between the surfaces of the adjacent fluid channel layers  104 . In various embodiments, the diffuser fins  120  may be integrally formed with the surfaces of the adjacent fluid channel layers  104 . For example, the diffuser fins  120   a  of first diffuser fins layer  102   a  are integrally formed with a topside surface  106   a  of first fluid channel layer  104   a  and an underside surface  108   b  of second fluid channel layer  104   b . The diffuser fins  120   b  of second diffuser fins layer  102   b  are integrally formed with topside surface  106   a  of second fluid channel layer  104   b  and the underside surface  108   c  of third fluid channel layer  104   c . Integrally forming diffuser fins layers  102  and fluid channel layers  104  tends prevent fluid from flowing between the surfaced of fluid channel layers  104  and the tips of diffuser fins  120 . 
     In various embodiments, diffuser fins layers  102  and fluid channel layers  104  may be formed using additive manufacturing. Additively manufacturing diffuser fins layers  102  and fluid channel layers  104  tends to allow for diffuser fin and fluid channel geometries that could not be produced through conventional manufacturing. In various embodiments, the entire layered diffuser-channel heat exchanger  100  may be printed in one additive manufacturing operation (e.g., diffuser fins layer  102  and fluid channel layer  104  is printed on the previously printed layer). In various embodiment, each pair of diffuser fins layer  102  and fluid channel layer  104  may be formed individually using additive manufacturing or a non-additive manufacturing technique (depending on the desired fluid channel/diffuser fins shape/patter) and may then be bonded together, for example, via brazing. For example, first fluid channel layer  104   a  and first diffuser fins layer  102   a  may be formed in a first forming step/operation. Second fluid channel layer  104   b  and second diffuser fins layer  102   b  may be formed separately from first fluid channel layer  104   a  and first diffuser fins layer  102   a  (e.g., in a second forming step/operation). Then first diffuser fins layer  102   a  may be bonded to underside surface  108   b  of second fluid channel layer  104   b.    
     With reference to  FIG.  3   , a portion of a diffuser fins layer  102  is illustrated. Diffuser fins  120  are formed over topside surface  106  and extending radially inward from outer circumference  116 . The locations of diffuser fins  120  may be selected to form approximately equal pressure drops in each of the airflow channels  122  formed between circumferentially adjacent diffuser fins  120 . 
     An orientation, a length, a density, and/or a number of the diffuser fins  120  may be tailored across the topside surface  106  of fluid channel layer  104  in order to control the heat flux profile and/or to be compatible with the manufacturing method. In various embodiments, diffuser fins  120  are angled to match a circumferential flow direction of the fluid entering the airflow channels  122  at inner circumference  124 . Stated differently, the angle of diffuser fins  120  relative to a line tangent to inner circumference  124  is approximately, equal to the angle of the flow direction of the fluid entering the channel, relative to the same tangent line. Stated yet another way, diffuser fins  120  are approximate parallel to the flow direction of fluid as it enters the airflow channel  122  defined by the diffuser fins  120 . As used in the previous context only, “approximately parallel” means±10° from parallel. 
     Due to the inner circumference  124  being less than the outer circumference, the diffuser fins  120  may become closer together in a radially inward direction. In this regard, a radial length of diffuser fins  120  may be varied across the diffuser fins layer  102 . In various embodiments, a first group  130  of diffuser fins  120  may have a first radial length L 1 , a second group  132  of diffuser fins  120  may have a second radial length L 2 , which is greater than radial length L 1 , and a third group  134  of diffuser fins  120  may have a third radial length L 3 , which is greater than radial length L 2 . The first group  130 , second group  132 , and third group  134  may all extend radially inward from outer circumference  116  (i.e., they may extend towards inner circumference  124 ). In various embodiments, the third group  134  may extend from outer circumference  116  to inner circumference  124 . While diffuser fins layer  102  is illustrated as having diffuser fins  120  of three (3) different length (e.g., first radial length R 1 , second radial length R 2 , and third radial length R 3 ), it is contemplated and understood that diffuser fins layer  102  may any number of diffuser fin lengths depending on the desired pressure drop between inner circumference  124  and outer circumference  116 . 
     Returning to  FIGS.  1 A and  1 B , a blower  140  may be located in a central cavity  142  of layered diffuser-channel heat exchanger  100 . Central cavity  142  is surrounded and/or bounded by the fluid channel layers  104  and the diffuser fins layers  102 . Blower  140  may include one or stage of rotating blades  144 . Blades  144  are configured to rotate about an axis A. As used herein, the terms “radial” and “radially” refer to directions perpendicular axis A, the terms “circumferential” and “circumferentially” refer to directions about axis A, and the terms “axial” and “axially” refer to directions parallel to axis A. 
     Blower  140  may include a motor  150  configured to drive rotation of the blades  144 . Rotation of blades  144  is configured to draw an airflow  156  into an inlet  152  of layered diffuser-channel heat exchanger  100 . Inlet  152  may be formed by blower  140 . In various embodiments, a cover plate  158  may be formed over the topmost diffuser fins layer  102 . Cover plate  158  has been removed from  FIG.  1 A  to illustrate details of the topmost diffuser fins layer  102 . In various embodiments, motor  150  may be located on an axially opposite end of layered diffuser-channel heat exchanger  100  relative to inlet  152 . 
     In accordance with various embodiments, a first stage  160  of blades  144  may direct a first portion  1561  of airflow  156  between topside surface  106   d  of fourth fluid channel layer  104   d  and cover plate  158 . Airflow portion  1561  flows radially outward through the airflow channels  122  ( FIG.  3   ) formed between circumferentially adjacent diffuser fins  120   d . A second stage  162  of blades  144  may direct a second portion  1562  of airflow  156  between topside surface  106   c  of third fluid channel layer  104   c  and underside surface  108   d  of fourth fluid channel layer  104   d . Airflow portion  1562  flows radially outward through the airflow channels  122  ( FIG.  3   ) formed between circumferentially adjacent diffuser fins  120   c . A third stage  164  of blades  144  may direct at third portion  1563  of airflow  156  between topside surface  106   b  of second fluid channel layer  104   b  and underside surface  108   c  of third fluid channel layer  104   c . Airflow portion  1563  flows radially outward through the airflow channels  122  ( FIG.  3   ) formed between circumferentially adjacent diffuser fins  120   b . A fourth stage  166  of blades  144  may direct a fourth portion  1564  of airflow  156  between topside surface  106   a  of first fluid channel layer  104   a  and underside surface  108   b  of second fluid channel layer  104   b . Airflow portion  1564  flows radially outward through the airflow channels  122  ( FIG.  3   ) formed between circumferentially adjacent diffuser fins  120   a . While blower  140  is illustrated as having four (4) stages of blades  144  (i.e., four coaxial fans), it is contemplated and understood that blower  140  may include any number of blade stages. In various embodiments, the number of blade stages may be equal to the number of diffuser fins layers  102 . 
     In accordance with various embodiments, the shape of airflow channels  122  tends to allow pressure losses to be recovered on the air side of layered diffuser-channel heat exchanger  100 . Blower  140  directs air flow through airflow channels  122 . As compared to heat exchanger systems having external fans, locating blower  140  in central cavity  142  tends to provide for greater heat transfer coefficients at the same fan power. In various embodiments, layered diffuser-channel heat exchanger  100  may be operated at lower fan power to achieve the same heat transfer coefficient as compared to an external fan systems. Locating blower  140  in central cavity  142  also reduces a size footprint of the heat exchanger (e.g., reduces the combined size of the heat exchanger and blower as compared to a traditional heat exchanger having a traditional fan or blower located exterior to the heat exchanger). 
     Referring to  FIG.  4   , a layered diffuser-channel heat exchanger  200  including a blower  240  having a central motor  250  is illustrated. In various embodiments, layered diffuser-channel heat exchanger  100  in  FIG.  1 B , may include blower  240  in place of blower  140 . In this regard, elements with like element numbering, as depicted in  FIG.  1 B , are intended to be the same and will not necessarily be repeated for the sake of brevity. 
     Blower  240  includes a motor  250  configured to drive rotation of a first stage  260  of the blades  244 , a second stage  262  of the blades  244 , a third stage  264  of the blades  244 , and a fourth stage  266  of blades  244 . Rotation of the first and second stages  260 ,  262  of blades  244  is configured to draw a first airflow  256  into a first airflow inlet  252  of layered diffuser-channel heat exchanger  200 . First airflow inlet  252  may be formed at a first axial end of blower  240 . Rotation of the third and fourth second stages  264 ,  266  of blades  244  is configured to draw a second airflow  258  into a second airflow inlet  270  of layered diffuser-channel heat exchanger  200 . Second airflow inlet  270  may be formed at a second axial end of blower  240 . In this regard, motor  250  is located axially between second stage  262  and fourth stage  266  of blades  244 . While blower  240  is illustrated as having four stage of blades  144  with two stages of blades on opposing sides of motor  250 , it is contemplated and understood that blower  240  may include any number of blade stages and that motor  250  may be located between any two of the blade stages. 
     In accordance with various embodiments, a first stage  260  of blades  244  may direct a first portion  256   1  of first airflow  256  between topside surface  106   d  of fourth fluid channel layer  104   d  and cover plate  158 . Airflow portion  256   1  flows radially outward through the airflow channels  122  ( FIG.  3   ) formed between circumferentially adjacent diffuser fins  120   d . Second stage  262  of blades  244  may direct a second portion  2562  of first airflow  256  between topside surface  106   c  of third fluid channel layer  104   c  and underside surface  108   d  of fourth fluid channel layer  104   d . Airflow portion  2562  flows radially outward through the airflow channels  122  ( FIG.  3   ) formed between circumferentially adjacent diffuser fins  120   c . Third stage  264  of blades  244  may direct a first portion  258   1  of second airflow  258  between topside surface  106   a  of first fluid channel layer  104   a  and underside surface  108   b  of second fluid channel layer  104   b . Airflow portion  258   1  flows radially outward through the airflow channels  122  ( FIG.  3   ) formed between circumferentially adjacent diffuser fins  120   a . Fourth stage  266  of blades  244  may direct a second portion  2582  of second airflow  258  between topside surface  106   b  of first fluid channel layer  104   a  and underside surface  108   c  of third fluid channel layer  104   c . Airflow portion  2582  flows radially outward through the airflow channels  122  ( FIG.  3   ) formed between circumferentially adjacent diffuser fins  120   b.    
     With reference to  FIG.  5   , a layered diffuser-channel heat exchanger  300  including a blower  340  having vane stages  310 ,  312 ,  314 ,  316  interleaved with a first stage  360 , a second stage  362 , a third stage  364 , and a fourth stage  366  of rotating blades  344  is illustrated. In various embodiments, layered diffuser-channel heat exchanger  100  in  FIG.  1 B , may include blower  340  in place of blower  140 . In this regard, elements with like element numbering, as depicted in  FIG.  1 B , are intended to be the same and will not necessarily be repeated for the sake of brevity. 
     Blower  340  includes one or more vane stages, such as first vane stage  310 , second vane stage  312 , third vane stage  314 , and fourth vane stage  316 , of non-rotating vanes  318 . Blower  340  includes a motor  350  configured to drive rotation of first stage  360 , second stage  362 , third stage  364  and fourth stage  366  of rotating blades  344 . Rotation of the of blades  344  is configured to draw an airflow  356  into an airflow inlet  352  of layered diffuser-channel heat exchanger  300 . Airflow inlet  352  may be formed at a first axial end of blower  340 . Motor  350  may be located at a second, opposite axial end of layered diffuser-channel heat exchanger  300 . Vanes  318  are configured to direct the airflow  356  to the area between adjacent fluid channel layers  104 . In this regard, vanes  318  direct the airflow  356  toward airflow channels  122  and diffuser fins  120 . 
     In various embodiments, the vanes  318  of first vane stage  310  may be configured to direct a first portion  3561  of airflow  356  into fourth diffuser fins layer  102   d . The vanes  318  of first vane stage  310  may also help direct a second portion  3562  of airflow  356  into third diffuser fins layer  102   c . In this regard, the vanes  318  of first vane stage  310  may direct airflow  356  generally away from inner circumference  124  ( FIG.  2 A ) of fourth fluid channel layer  104   d.    
     The vanes  318  of second vane stage  312  may be configured to direct second portion  3562  of airflow  356  into third diffuser fins layer  102   c . The vanes  318  of second vane stage  312  may also help direct a third portion  3563  of airflow  356  into second diffuser fins layer  102   b . In this regard, the vanes  318  of second vane stage  312  may direct airflow  356  generally away from inner circumference  124  ( FIG.  2 A ) of third fluid channel layer  104   c.    
     The vanes  318  of third vane stage  314  may be configured to direct third portion  3563  of airflow  356  into second diffuser fins layer  102   b . The vanes  318  of third vane stage  314  may also help direct a fourth portion  3564  of airflow  356  into first diffuser fins layer  102   a . In this regard, the vanes  318  of third vane stage  314  may direct airflow  356  generally away from inner circumference  124  ( FIG.  2 A ) of second fluid channel layer  104   b.    
     The vanes  318  of fourth vane stage  316  may be configured to direct fourth portion  3564  of airflow  356  into first diffuser fins layer  102   a . In this regard, the vanes  318  of fourth vane stage  316  may direct airflow  356  generally away from inner circumference  124  ( FIG.  2 A ) of first fluid channel layer  104   a . While layered diffuser-channel heat exchanger  300  is illustrated as having four (4) diffuser fins layers  102  and fluid channel layers  104 , and blower  340  is illustrated with four (4) stages of vanes and four (4) stages of blades, it is contemplated and understood that layered diffuser-channel heat exchanger  300  may include any number of diffuser fins layers  102  and fluid channel layers  104 , and blower  340  may include any number of stages of vanes and stages of blades. In various embodiments, the number of stages of vanes and/or the number of stages of blades may be equal to the number of diffuser fins layers  102 . In various embodiments, blower  340  may include a central motor, similar to blower  240  and motor  250  in  FIG.  4   . 
     With reference to  FIG.  6   , a layered diffuser-channel heat exchanger  400  including angled diffuser fins layers  102  and fluid channel layers  104  is illustrated. Elements in  FIG.  6    with like element numbering, as depicted in  FIG.  1 B , are intended to be the same and will not necessarily be repeated for the sake of brevity. In various embodiments, layered diffuser-channel heat exchanger  400  includes a blower  440  having first stage  410 , second stage  412 , a third stage  414 , and a fourth stage  416  of non-rotating vanes  418  interleaved with a first stage  460 , a second stage  462 , a third stage  464 , and a fourth stage  466  of rotating blades  444 . 
     Blower  440  includes a motor  450  configured to drive rotation of first stage  460 , second stage  462 , third stage  464  and fourth stage  466  of rotating blades  444 . Rotation of the of blades  444  is configured to draw an airflow  456  into an airflow inlet  452  of layered diffuser-channel heat exchanger  400 . Airflow inlet  452  may be formed at a first axial end of blower  440 . Motor  450  may be located at a second, opposite axial end of layered diffuser-channel heat exchanger  400 . Vanes  418  are configured to direct the airflow  456  to the area between adjacent fluid channel layers  104 . In this regard, vanes  418  direct the airflow  456  toward airflow channels  122  and diffuser fins  120 . 
     In various embodiments, the vanes  418  of first vane stage  410  may be configured to direct a first portion  456   1  of airflow  456  into fourth diffuser fins layer  102   d . The vanes  418  of second vane stage  412  may be configured to direct a second portion  4562  of airflow  456  into third diffuser fins layer  102   c . The vanes  418  of third vane stage  414  may be configured to direct a third portion  4563  of airflow  456  into second diffuser fins layer  102   b . The vanes t 18  of fourth vane stage  416  may be configured to direct a fourth portion  4564  of airflow  456  into first diffuser fins layer  102   a.    
     In accordance with various embodiments, diffuser fins layers  102  and fluid channel layers  104  are configured to be approximately parallel to flow direction of the airflow  456  as it exits vanes  418 . For example, topside surface  106   d  of fourth fluid channel layer  104   d  may be approximately parallel to the direction of first airflow portion  456   1  as first airflow portion  456   1  exits vanes  418  of first vane stage  410 . In this regard, the angle of diffuser fins layers  102  and fluid channel layers  104  may be configured to decrease, or minimize, the directional changes in airflow  456  as it enters airflow channels  122  ( FIG.  3   ). For example, the angle of topside surface  106   d , relative to axis A, may be approximately equal to the angle of the flow direction of the first airflow portion  456   1 , relative to axis A. In various embodiments, topside surface  106   d  is not perpendicular to axis A. For example, the angle of topside surface  106   d , relative to axis A, may be between 100° and 160°, between 105° and 150°, between 110° and 135°, or any other desired angle. The underside surface  159  of cover plate  158  may be approximately parallel to topside surface  106   d . In various embodiments, first vane stage  410  may be eliminated and the orientation of topside surface  106   d  may be approximately parallel to the direction of the first airflow portion  456   1  exiting first blade stage  460 . As used in the previous paragraph, “approximately parallel” means±5° from parallel and “approximately equal” means±5°. 
     In various embodiments, topside surface  106   c  of third fluid channel layer  104   c  may be approximately parallel the flow to direction of second airflow portion  4562  as it exits vanes  418  of second vane stage  412 . For example, the angle of topside surface  106   c , relative to axis A, may be approximately equal to the angle of the flow direction of the second airflow portion  4562 , relative to axis A. In various embodiments, topside surface  106   c  is not perpendicular to axis A. For example, the angle of topside surface  106   c , relative to axis A, may be between 100° and 160°, between 105° and 150°, between 110° and 135°, or any other desired angle. The underside surface  108   d  of fourth fluid channel layer  104   d  may be approximately parallel to topside surface  106   c . In various embodiments, second vane stage  412  may be eliminated and the orientation of topside surface  106   c  may be approximately parallel to the direction of the second airflow portion  4562  exiting second blade stage  462 . As used in the previous paragraph, “approximately parallel” means±5° from parallel and “approximately equal” means±5°. 
     In various embodiments, topside surface  106   b  of second fluid channel layer  104   b  may be approximately parallel the flow to direction of third airflow portion  4563  as third airflow portion  4563  exits vanes  418  of third vane stage  414 . For example, the angle of topside surface  106   b , relative to axis A, may be approximately equal to the angle of the flow direction of the third airflow portion  4563 , relative to axis A. In various embodiments, topside surface  106   b  is not perpendicular to axis A. For example, the angle of topside surface  106   b , relative to axis A, may be between 100° and 160°, between 105° and 150°, between 110° and 135°, or any other desired angle. The underside surface  108   c  of third fluid channel layer  104   c  may be approximately parallel to topside surface  106   b . In various embodiments, third vane stage  414  may be eliminated and the orientation of topside surface  106   b  may be approximately parallel to the direction of the third airflow portion  4563  exiting third blade stage  464 . As used in the previous paragraph, “approximately parallel” means±5° from parallel and “approximately equal” means±5°. 
     In various embodiments, topside surface  106   a  of first fluid channel layer  104   a  may be approximately parallel the flow to direction of fourth airflow portion  4564  as it exits vanes  418  of fourth vane stage  416 . For example, the angle of topside surface  106   a , relative to axis A, may be approximately equal to the angle of the flow direction of the fourth airflow portion  4564 , relative to axis A. In various embodiments, topside surface  106   a  is not perpendicular to axis A. For example, the angle of topside surface  106   a , relative to axis A, may be between 100° and 160°, between 105° and 150°, between 110° and 135°, or any other desired angle. The underside surface  108   b  of second fluid channel layer  104   b  may be approximately parallel to topside surface  106   a . In various embodiments, fourth vane stage  416  may be eliminated, as the orientation of topside surface  106   b  may be approximately parallel to the direction of the fourth airflow portion  4564  as it exits further blade stage  466 . As used in the previous paragraph, “approximately parallel” means±5° from parallel and “approximately equal” means±5°. 
     While layered diffuser-channel heat exchanger  400  is illustrated as having four (4) diffuser fins layers  102  and fluid channel layers  104 , and blower  440  is illustrated with four (4) stages of vanes and four (4) stages of blades, it is contemplated and understood that layered diffuser-channel heat exchanger  400  may include any number of diffuser fins layers  102  and fluid channel layers  104 , and blower  440  may include any number of stages of vanes and/or stages of blades. In various embodiments, the number of stages of vanes and/or the number of stages of blades may be equal to the number of diffuser fins layers  102 . In various embodiments, blower  440  may include a central motor, similar to blower  240  and motor  250  in  FIG.  4   . 
     With reference to  FIG.  7   , a method  500  of making a layered diffuser-channel heat exchanger is also disclosed herein. In accordance with various embodiments, method  500  may comprise forming a first fluid channel layer having a first fluid channel located between a first surface and a second surface of the first fluid channel layer (step  502 ), forming a plurality of first diffuser fins extending from the first surface of the first fluid channel layer (step  504 ), and forming a second fluid channel layer over the plurality of first diffuser fins, with the second fluid channel layer having a second fluid channel located between a topside surface and a underside surface of the second fluid channel layer (step  506 ). Method  500  may further include forming a plurality of second diffuser fins extending from the topside surface of the second fluid channel layer (step  508 ). 
     In various embodiments, the method  500  may further comprise locating a blower in a central cavity surrounded by the first fluid channel layer, the plurality of first diffuser fins, and the second fluid channel layer (step  510 ). In various embodiments, the underside surface of the second fluid channel may be integrally formed with the plurality of first diffuser fins. In various embodiments, method  500  may comprise forming the first fluid channel layer, the plurality of first diffuser fins, and the second fluid channel layer using additive manufacturing. 
     In various embodiments, the method  500  may further comprise locating a first stage of stationary vanes axially between a first stage of blades of the blower and a second stage of blades of the blower. The first stage of stationary vanes may be configured to direct airflow between the first surface of a first fluid channel layer and the underside surface of a second fluid channel layer. 
     In various embodiments, the method  500  may further comprise orienting the first surface of the first fluid channel at a first non-perpendicular angle relative to an axis of rotation of first stage of blades of the blower, and orienting the topside surface of the second fluid channel at a second non-perpendicular angle relative to the axis of rotation of first stage of blades of the blower. The second non-perpendicular angle may be equal to or different from the first non-perpendicular angle. 
     In various embodiments, step  504  may comprise forming a first group of the first diffuser fins having a first radial length, forming a second group of the first diffuser fins having a second radial length greater than the first radial length, and forming a third group of diffuser fins having a third radial length greater the second radial length. Each of the first group of first diffuser fins, the second group of first diffuser fins, and the third group of first diffuser fins extends radially inward from an outer circumference of the first fluid channel layer. 
     Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. 
     The scope of the disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” It is to be understood that unless specifically stated otherwise, references to “a,” “an,” and/or “the” may include one or more than one and that reference to an item in the singular may also include the item in the plural. All ranges and ratio limits disclosed herein may be combined. 
     Moreover, where a phrase similar to “at least one of A, B, and C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Elements and steps in the figures are illustrated for simplicity and clarity and have not necessarily been rendered according to any particular sequence. For example, steps that may be performed concurrently or in different order are illustrated in the figures to help to improve understanding of embodiments of the present disclosure. 
     Systems, methods, and apparatus are provided herein. In the detailed description herein, references to “one embodiment”, “an embodiment”, “various embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments. 
     Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element is intended to invoke 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.