Multi-stage air movers for cooling computer systems and for other uses

Multi-stage air movers for cooling computers and other systems are described herein. In one embodiment, a computer system includes a computer cabinet holding a plurality of computer modules. The computer cabinet includes an air inlet and an air outlet. The computer system further includes a multi-stage air mover configured to move a flow of cooling air from the air inlet, past the plurality of computer modules, and out the computer cabinet via the air outlet.

TECHNICAL FIELD

The following disclosure relates generally to computer air conditioning systems and, more particularly, to air movers for use with such air conditioning systems.

BACKGROUND

Supercomputers and other large computer systems typically include a large number of computer cabinets arranged in close proximity to each other.FIG. 1, for example, illustrates a portion of a prior art supercomputer system100having plurality of computer cabinets110arranged in a bank. The computer cabinets110are arranged in a bank to conserve floor space and increase computational speed by reducing cable lengths between cabinets. Each of the computer cabinets110includes a plurality of computer module compartments118(identified individually as a first module compartment118a, a second module compartment118b, and a third module compartment118c). Each module compartment118holds a plurality of computer modules112. Like the computer cabinets110, the computer modules112are also positioned in close proximity to each other to conserve space and increase computational speed. Each of the computer modules112can include a motherboard electrically connecting a plurality of processors, memory modules, routers, and other microelectronic devices together for data and/or power transmission.

Many of the electronic devices typically found in supercomputers, such as fast processing devices, generate considerable heat during operation. This heat can damage the device and/or degrade performance if not dissipated during operation. Consequently, supercomputers typically include both active and passive cooling systems to maintain device temperatures at acceptable levels.

To dissipate heat generated by the computer modules112, the prior art supercomputer system100further includes a plurality of centrifugal fans120mounted to upper portions of corresponding computer cabinets110. In operation, each of the centrifugal fans120draws cooling air into the corresponding computer cabinet110through a front inlet114and/or a back inlet115positioned toward a bottom portion of the computer cabinet110. The cooling air flows upwardly through the computer cabinet110, past the computer modules112, and into a central inlet122of the fan120. The centrifugal fan120then exhausts the cooling air outward in a radial pattern through a circumferential outlet124.

One problem associated with the prior art supercomputer system100is the inability of the centrifugal fan120to move a sufficient amount of air through the computer cabinet110for adequate cooling when the density of the computer modules112increases. As more computer modules112are installed in a given space (e.g., by decreasing the spacing between two adjacent computer modules112), available flow paths for cooling air decrease, thereby increasing the pressure drop as the cooling air flows past the computer modules112. The centrifugal fan120typically has a generally flat operating curve (i.e., the generated pressure differentials are nearly constant with respect to different volumetric flow rates). As a result, as the centrifugal fan120increases the output pressure differential to compensate for the increased pressure drop, the flow rate of the cooling air through the computer cabinet110is significantly reduced. The reduction in cooling air flow can cause overheating of the computer modules112, and thus adversely affect performance of the computer system100.

Conventional techniques for increasing cooling air flow in densely packed computer cabinet110include increasing the size of the centrifugal fan120and increasing the operating speed of the centrifugal fan120. There are a number of shortcomings associated with each of these solutions. First, increasing the size of the centrifugal fan120increases the power consumption of the centrifugal fan120. In addition, the computer cabinet110may not have enough space to accommodate a fan120of increased size. Second, increasing the operating speed of the centrifugal fans120can cause a substantial increase in operating noise and power consumption.

DETAILED DESCRIPTION

The following disclosure describes several embodiments of multi-stage air movers for use with computer cabinet air conditioning systems and other air conditioning systems. One aspect of the invention is directed toward a computer system that includes a computer cabinet holding a plurality of computer modules. The computer cabinet has an air inlet and an air outlet. The computer system further includes a multi-stage air mover carried by the computer cabinet. The multi-stage air mover is configured to move a flow of cooling air from the air inlet, past the plurality of computer modules, and out the computer cabinet via the air outlet. The multi-stage air mover includes first and second rotating blade sets in generally annular arrangements about an axis of rotation. The first and second rotating blade sets are at least approximately aligned in a radial direction extending outwardly from the longitudinal axis of rotation. Here, the term “radial direction” generally refers to a direction that is perpendicular to the longitudinal axis of rotation.

A computer system configured in accordance with another aspect of the invention includes a computer module and an air mover positioned inside a computer cabinet. The air mover includes a plurality of radially positioned rotating blade sets that are configured to move a flow of cooling air through the computer cabinet and past the computer module. In this aspect of the invention, the air mover can also include a stationary blade set positioned at least partially between two adjacent rotating blade sets.

A further aspect of the invention is directed toward an air mover assembly for use with a computer cabinet. The air mover assembly includes a first multi-stage air mover attached to a mounting plate having first and second openings. The first multi-stage air mover has a first outlet in fluid communication with the first opening. The air mover assembly also includes a second multi-stage air mover attached to the mounting plate. The second multi-stage air mover has a second outlet in fluid communication with the second opening. A motor is operatively coupled to at least the first multi-stage air mover to drive air through the computer cabinet via the first opening in the mounting plate.

A further aspect of the invention is directed toward a centrifugal air mover that includes a rotating portion carrying a plurality of blade sets. Each of the blade sets is in a generally annular arrangement about an axis of rotation. Further, the blade sets are at least approximately aligned in a radial direction extending outwardly from the longitudinal axis of rotation. The air mover also includes a stationary portion carrying at least one blade set positioned at least partially between two adjacent blade sets of the rotating portion.

A further aspect of the invention is directed toward a method for cooling a plurality of computer modules carried by a computer cabinet. The computer cabinet includes an air inlet and an air outlet. The method includes positioning a multi-stage air mover inside the computer cabinet proximate to the air inlet, and operating the multi-stage air mover to drive a flow of cooling air from the air inlet through the computer cabinet, past the computer modules, and into the room through the air outlet. In this aspect of the invention, the multi-stage air mover includes first, second, and third blade sets at least approximately aligned in a radial direction extending outwardly from an axis of rotation. Each of the blade sets is in a generally annular arrangement about the axis of rotation, and the third blade set is positioned at least partially between the first and second blade sets.

Specific details of several embodiments of the invention are described below with reference toFIGS. 2-6to provide a thorough understanding of the embodiments. Other details describing well-known structures and systems often associated with computer cabinets and associated air conditioning equipment, however, are not set forth below to avoid obscuring the description of the various embodiments. Those of ordinary skill in the art will understand that the invention may have other embodiments in addition to those described below. Such embodiments may lack one or more of the elements described below. Alternatively, such embodiments may include other elements in addition to those described below.

In the Figures, identical reference numbers identify identical or at least generally similar elements. To facilitate the discussion of any particular element, the most significant digit or digits of any reference number refer to the Figure in which that element is first introduced. Element202, for example, is first introduced and discussed with reference toFIG. 2.

FIG. 2is a partially exploded isometric view of a computer cabinet210that carries a plurality of multi-stage air movers220(“air movers220”) configured in accordance with an embodiment of the invention. In the illustrated embodiment, some external panels of the computer cabinet210have been removed for clarity. Many features of the computer cabinet210can be at least generally similar in structure and function to corresponding features of the computer cabinet110described above with reference toFIG. 1. For example, the computer cabinet210can include a plurality of computer module compartments218holding a plurality of computer modules212in vertical, edge-wise orientation. The computer cabinet210can further include a front inlet214and a back inlet215positioned toward a bottom portion of the computer cabinet210, and an outlet224positioned toward a top portion of the computer cabinet210.

In one aspect of this embodiment, the computer cabinet210includes an air mover assembly202positioned toward the bottom portion of the computer cabinet210to drive cooling air through the computer cabinet210. The air mover assembly202can include a plurality of air movers220(identified individually as air movers220a-d) attached to a mounting plate230. The mounting plate230includes a plurality of openings204(identified individually as openings204a-d) positioned proximate to the air movers220. One embodiment of the air mover assembly202is described in more detail below with reference toFIG. 3.

The computer cabinet210can optionally include a distribution member222positioned toward the bottom portion of the computer cabinet210above the openings204. The distribution member222can include features that influence the flow pattern of cooling air in the computer cabinet210. For example, the distribution member222can include a plurality of apertures, channels, vanes, or other structures configured to equalize the flow of cooling air over the cross-section of the computer cabinet210. Although the illustrated embodiment shows one distribution member222positioned proximate to the air mover assembly202, in other embodiments, the computer cabinet210can include other distribution members222in other positions, such as in each computer module compartment218. Alternatively, the distribution member222can be omitted.

The computer cabinet210can also include one or more sensors (not shown) for monitoring operating conditions of the computer modules212. For example, the computer cabinet210can include one or more temperature sensors (e.g., thermocouples, RTD, or inferred temperature monitors), flow sensors (e.g., flow switches and flow transmitters), pressure sensors (e.g., pressure switches and pressure transmitters), and/or other types of sensors capable of measuring parameters indicative of the operating conditions of the computer modules212. For instance, the computer cabinet210can include thermocouples (not shown) positioned in each computer module compartment218to monitor operating temperatures inside the computer cabinet210. In another example, the computer cabinet210can include a flow transmitter (not shown) positioned toward the top portion of the computer cabinet210to measure a cooling air flow rate in the top portion.

In operation, the air mover assembly202draws cooling air (represented by arrows221) into the computer cabinet210via the front inlet214and the back inlet215. The air movers220compress the cooling air and drive it upwardly through the openings204and the distribution member222. The cooling air then flows generally evenly through the computer cabinet210and past the computer modules212before exiting the computer cabinet210through the outlet224. As the cooling air221moves past the computer modules212, the cooling air221carries away heat generated during operation of the computer modules212. The operating conditions of the computer modules212can be monitored with one or more of the optional sensors described above.

FIG. 3is an enlarged isometric view of the air mover assembly202ofFIG. 2. In the embodiment ofFIG. 3, the air movers220are arranged in face-to-face pairs. A motor332is operatively coupled to each pair of opposing air movers220by a corresponding shaft338. Each of the air movers220includes an air inlet334and an air outlet336. The air outlet336is in fluid communication with the corresponding opening204of the mounting plate230. For example, the multi-stage air mover220aincludes an air outlet336athat is in fluid communication with the opening204a.

Optionally, the air mover assembly202can further include two speed controllers331that are attached to the mounting plate230and operatively coupled to the motors332. The speed controllers331can be configured to dynamically adjust operating speeds of the motors332. For example, the speed controllers331can include variable frequency drives (“VFDs”) for adjusting power frequencies applied to the motors332to change rotating speeds. One example of a suitable VFD is the “Sub-micro AC drive” produced by AC Technology Corporation of Uxbridge, Mass. In other embodiments, other suitable VFDs can be used.

In operation, the motors332drive the pairs of corresponding air movers220to move a flow of cooling air through the computer cabinet210. Specifically, the cooling air enters the air movers220via the annular or circular air inlets334on the inboard side of the air movers220. The air movers220then compress the cooling air and discharge it through the openings204. The air movers220provide sufficient pressure to drive the cooling air past the densely-packed computer modules212as further described below with reference toFIGS. 4-6. Optionally, the motor speeds can be regulated using the speed controllers331to achieve a desired flow rate at the top portion of the computer cabinet210or a desired operating temperature inside the computer cabinet210.

Although the illustrated embodiment shows two pairs of air movers220in face-to-face arrangements with motors positioned there between, in other embodiments, air mover assemblies configured in accordance with the present disclosure can include more or fewer air movers in different arrangements. For example, in another embodiment, the air mover assembly202can include one pair of face-to-face air movers220operatively coupled to a motor positioned there between. In a further embodiment, an air mover assembly202configured in accordance with the present disclosure can include multiple pairs of air movers220arranged in tandem. Accordingly, the present invention is not limited to an air mover assembly202having two pairs of air movers220in the particular arrangement ofFIG. 3.

FIG. 4is an isometric view of one of the air movers220(e.g. the air mover220a) ofFIG. 3, configured in accordance with an embodiment of the invention. A plurality of mounting flanges448are positioned around the air outlet336and configured to attach the air mover220to the mounting plate230(FIGS.2and3). The air mover220can include a rotating portion444and a stationary portion446carried by a housing440. The air inlet334is positioned adjacent to the stationary portion446and in fluid communication with the rotating portion444. The air mover220can further include a central coupler442configured to operatively couple the rotating portion444to the motor332.

FIG. 5is a partially exploded isometric view of the air mover220ofFIG. 4, illustrating a number of features in greater detail. In one aspect of the embodiment, the housing440includes an internal cavity570. The internal cavity570has a generally circular shape configured to accommodate the rotating portion444and the stationary portion446. The internal cavity570is larger than the rotating portion444, thereby forming an annular gap between the housing440and the rotating portion444when assembled. The housing440can be constructed of any suitable material including, for example, ductile iron, cast aluminum, stainless steel, plastic, and/or any other material having sufficient rigidity.

In the illustrated embodiment, the rotating portion444includes a first blade set556and a second blade set554that are carried by a back plate558. The first and second blade sets554and556form generally annular arrangements about a longitudinal axis of rotation572. A first annular face plate560is attached to the first blade set554, and a second annular face plate562is attached to the second blade set556. The back plate558and face plates562can be constructed from any suitable material including, for example, ductile iron, cast aluminum, stainless steel, plastic, and/or any other material having sufficient rigidity.

In the illustrated embodiment, the stationary portion446can include a third blade set552attached to a stationary plate550. The stationary plate550includes an opening551generally concentric to the axis of rotation572. The opening551provides access to allow the rotating portion444to engage the motor332with the central coupler442. The opening551has a larger diameter than the motor332to provide an annular gap that forms the air inlet334. The stationary plate550can be constructed from any suitable material including, for example, fiberglass, plastic, paper, cast aluminum, stainless steel, and/or any other material having sufficient rigidity, strength, flexibility, etc.

When assembled as shown inFIG. 4, the blade sets552,554, and556can be at least approximately aligned in a radial direction extending outwardly from the longitudinal axis of rotation572. In this regard, the stationary third blade set552can be positioned at least partially between the rotating first and second blade sets554and556to direct the compressed air from the first blade set556to the second blade set554, as further described in more detail below with reference toFIG. 6.

FIG. 6is a side cross-sectional view of the air mover220ofFIG. 4, configured in accordance with an embodiment of the invention. In one aspect of this embodiment, each of the rotating blade sets554and556can be concentrically positioned about the longitudinal axis of rotation572. The two rotating blade sets554and556are spaced apart radially by an annular gap configured to accommodate the stationary blade set552.

In another aspect of the invention, each of the rotating blade sets554and556can include a plurality of forward curved blades660(identified individually as forward curved blades660aand660b, respectively). the term “forward curved” generally refers to having a radially outward curve that is at least partially in a direction of rotation. The forward curved blades660aand660bcan have generally similar curvatures and shapes, and can be generally parallel to each other as illustrated inFIG. 6. In other embodiments, the blades660acan have different curvatures and/or shapes. For example, the blades660can be straight, backward curved, or a combination of straight and curved blades. The term “backward curved” generally refers to having a radially outward curve that is at least partially opposite to a direction of rotation. The blades660can be constructed from cast aluminum, stainless steel, titanium, brass, or any other suitable material with sufficient strength, rigidity, etc.

In another aspect of the invention, the stationary blade set552can include, for example, a plurality of backward curved straightening vanes664configured to direct the compressed cooling air from the first blade set556to the second blade set554. The term “straightening vanes” generally refers to structures that modify (e.g., straighten) a fluid flow path. In the illustrated embodiment, the straightening vanes664are positioned between the first rotating blade set554and the second rotating blade set556. The straightening vanes664can be constructed from cast aluminum, stainless steel, titanium, brass, or any other suitable material with sufficient strength, rigidity, etc.

In operation, the motor332(FIGS. 4 and 5) drives the rotating blade sets554and556in a counter-clockwise direction (as indicated by arrow A) about the axis of rotation572. As the blades rotate, cooling air621(represented by arrows621a) enters the air mover220via the air inlet334. The first rotating blade set556applies a centrifugal force to increase kinetic energy of the cooling air621as it drives the air outwardly and into the stationary blade set552(represented by arrow621b). The stationary blade set552directs the cooling air621exiting the first blade set556into the second rotating blade set554(represented by arrow621c). The second rotating blade set556then applies additional centrifugal force to the redirected cooling air621to further increase the kinetic energy of the cooling air621as it exits the second rotating blade set554. The cooling air621then flows around the housing440(represented by arrows621eand621f) before exiting the air mover220via the air outlet336(represented by arrow621g).

There are a number of advantages associated with the air mover220. One advantage is that the air mover220can achieve a significantly higher pressure than conventional air movers of similar size. Without being bound by theory, it is believed that directing the cooling air from the first rotating blade set556through the straightening vanes664allows the second rotating blade set554to capture the large tangential velocity of the cooling air leaving the first rotating blade set556. As a result, the cooling air exiting the second rotating blade set554has gone through a multi-stage boost to achieve higher pressures than can be achieved with conventional, single stage air movers of comparable size. Accordingly, the rotating blade sets554and556form compression stages that incrementally increase the air pressure of the cooling air. Another advantage of the air mover220is that it is relatively efficient from a power consumption standpoint because it can produce sufficient discharge pressures to move the cooling air through the computer cabinet210at relatively low operating speeds. A further advantage related to the relative low operating speed is that the air mover220is relatively quiet.

Although the illustrated embodiment shows two rotating blade sets and one stationary blade set, in other embodiments, an air mover220configured in accordance with the present disclosure can include more or fewer rotating blade sets and/or more or fewer stationary blade sets in similar or different arrangements. For example, in another embodiment, the rotating portion444can include three blade sets and the stationary portion can include two blade sets interposed between the rotating blade sets. That is, each of the two stationary blade sets can be positioned at least partially between two adjacent rotating blade sets. In a further embodiment, an air mover configured in accordance with the present disclosure can include straight and/or backward curved blades in a generally annular arrangement about the axis of rotation572. Accordingly, the present invention is not limited to air movers having two rotating blade sets and one stationary blade set in the particular arrangement ofFIG. 6, but extends to all other configurations that fall within the scope of the present disclosure.

Furthermore, even though embodiments of the present invention have been described above in the context of air movers for use in computer cabinets, the invention is not limited to air movers. For example, other embodiments can be used to move other types of materials, such as gaseous materials (e.g., nitrogen, oxygen, argon, hydrogen, carbon dioxide, natural gas, and steam), liquid materials (e.g., water, oil, and gasoline), or granulized solids (e.g., laundry detergent powder and cement). The device can be used in chemical and/or physical processes, such as chemical processing, oil refining, food processing, etc.

From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the invention. For example, although elements of the invention described above have been presented in one or more arrangements, in other embodiments, other arrangements are possible depending on the particular situation. Further, while advantages associated with certain embodiments of the invention have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited, except as by the appended claims.