Patent Grant
8801374
This invention relates to apparatus and methods for cooling electronic devices, such as, for example, fan trays having stator blades for improving the air flow performance of the fans mounted thereto.
Data processing units, such as routers, switches, servers, storage devices, and/or components included within a core switch fabric of a data center, include electronic devices (e.g., amplifiers, signal processors, optical transceivers or the like) that can generate heat during their operation. To increase the processing speed and/or processing capacity, some known data processing units include high power electronic devices, more densely packaged electronic devices and/or the like. Accordingly, some known data processing units include forced air cooling systems to prevent overheating of the electronic devices contained therein.
Such known data processing units can include, for example, one or more fan trays upon which fans and/or blowers are mounted. The fan trays can be mounted within the chassis (or frame) of the data processing unit, and can produce a pressurized air flow within the channels, ducts and/or air flow pathways of the chassis to cool the electronic devices. Such fan trays further facilitate the mounting and electrical connections used to operate the fans and/or blowers. For example, some known fan trays can be configured to be contained within a specific “bay” defined within the chassis. Such fan trays can be referred to as “rack mounted” or “rack mountable” fan trays.
The selection of the air flow device (e.g., the fan or blower) for cooling known data processing units can be based on a variety of constraints, including, for example, the desired flow rate and pressure of the air flow, the power requirements, the cost of the device and/or the size of the device. In view of these criteria, some known data processing units include axial air flow devices, which produce an air flow that is substantially parallel to the axis of rotation of the rotor (e.g., the blade, propeller or impeller). Axial air flow devices generally produce a higher airflow, albeit at lower pressures, than a similarly-sized centrifugal blower. In particular, some known data processing units include one or more tubeaxial fans mounted to a fan tray.
Known axial fans used for cooling data processing units, however, can be susceptible to flow pulsations, high noise emissions and/or operation at low pressure or low efficiency. Accordingly, some data processing units include axial fans mounted in series, dual-rotor axial fans or the like. Such axial fan configurations, however, result in increased size and/or cost. Moreover, such axial fan configurations are often configured for a specific chassis design, and are not easily used in multiple different designs.
Thus, a need exists for improved apparatus and methods for improving the efficiency and flexibility of cooling systems for data processing units.
Fan tray assemblies for cooling electronic devices in data processing units are described herein. In some embodiments, an apparatus includes a fan tray and a stator member. The fan tray is configured to be mounted within a data processing unit, and defines an opening. The fan tray is configured to be coupled to a fan such that the fan and the opening collectively define a portion of an air flow path. The stator member includes multiple stator blades. The stator member is separate from the fan and configured to be coupled to the fan tray such that the stator blades are within the air flow path.
Fan tray assemblies for cooling electronic devices in data processing units are described herein. In some embodiments, an apparatus includes a fan tray and a stator member. The fan tray is configured to be mounted within a data processing unit, and defines an opening. The fan tray is configured to be coupled to a fan such that the fan and the opening collectively define a portion of an air flow path. The stator member includes multiple stator blades. The stator member is separate from the fan and configured to be coupled to the fan tray such that the stator blades are within the air flow path. In some embodiments, for example, the stator member can be coupled to the fan tray such that the stator blades are substantially within the opening.
In some embodiments, an apparatus includes a fan tray and a stator member. The fan tray is configured to be mounted within a data processing unit and to be coupled to at least one fan. The stator member includes multiple stator blades configured to reduce a non-axial component of an air flow produced by the fan. The stator member is configured to be coupled to the fan tray independently from the fan being coupled to the fan tray.
In some embodiments, an apparatus includes a fan tray configured to be mounted within a data processing unit. The fan tray has a fan mounting portion and a stator portion. The fan mounting portion is configured to be coupled to a fan such that the fan and an opening defined by the fan mounting portion collectively define a portion of an air flow path. The stator portion includes a set of stator blades within the air flow path. The stator portion and the fan mounting portion are monolithically constructed.
As used herein the term “data processing unit” refers to, for example, any computer, electronic switch, switch fabric, portion of a switch fabric, router, host device, data storage device, line card or the like used to process, transmit and/or convey electrical and/or optical signals. A data processing unit can include, for example, a component included within an electronic communications network. In some embodiments, for example, a data processing unit can be a component included within or forming a portion of a core switch fabric of a data center. In other embodiments, a data processing unit can be an access switch located at an edge of a data center, or a host or peripheral device (e.g., a server) coupled to the access device. For example, an access switch can be located on top of a chassis containing several host devices.
As used herein the term “electronic device” refers to any component within a data processing unit that is configured to perform an electronic function associated with the data processing unit. An electronic device can include, for example, a switching device, a converter, a receiver, a transmitter, a signal conditioner, an amplifier or the like. In some embodiments, an electronic device can include an optical transceiver configured to convert electrical signals into optical signals and vice versa.
The rack units 104 include the line cards and electronic devices that perform, at least in part, the functions of the data processing unit 100. For example, in some embodiments, the rack units 104 can include a printed circuit board (not shown in
The fan tray assembly 140 is configured to be mounted within the internal region 103 of the chassis 102 (as shown by the arrow AA in
The fan tray assembly 140 includes a fan tray 143, four fans 110 and four stator members 160. As shown in
The fan tray 143 can be any suitable structural member for supporting the fans 110 and coupling the fan tray assembly 140 within the chassis 102. In particular, the fan tray 143 defines a set of openings 142 that correspond to each of the fans 110. Each fan 110 is coupled to the fan tray 143 such that the fan 110 and the opening 142 collectively define a portion of an air flow path 106 (shown in
The stator member 160 includes a set of stator blades 164 and is disposed between the fan 110 and the fan tray 143. As shown in
In some embodiments, for example, the stator blades 164 and the rotor blades 124 are configured to cooperatively produce a substantially axial air flow (i.e., an air flow that is substantially parallel to the fan axis Af) within the flow path 106.
By eliminating and/or reducing a portion of the non-axial component of the air flow that would otherwise be produced by the fan 110, the stator blades 164 can improve the performance of the fan 110. In this manner, the stator blades 164 can, at least in part, tailor the air flow characteristics for the data processing unit 100. Similarly stated, the stator blades 164 can improve the performance of the fan 110 to accommodate the system pressure drop, cost, space and/or power constraints of the data processing unit 100. For example,
As illustrated by the fan performance curves 270, 272, the pressure produced by the fan (plotted on the Y-axis) generally increases as the air flow produced by the fan (plotted on the X-axis) decreases. Similarly stated, as the fan produces a higher pressure (e.g., to overcome restrictions and/or frictional losses within the air flow path 106), the air flow rate produced by the fan will generally decrease. As with most axial fans, however, during operation of the fan a region of instability exists beyond which the rotor blades 124 stall. The regions of instability are shown as the shaded region 271 on performance curve 270 and shaded region 273 on performance curve 272. In the regions 271 and 273 of the fan performance curve the design of the rotor blades 124 is such that, under certain operating conditions, the pressure produced by the fan decreases with decreasing air flow. Operating the fan within the region of instability can result in pulsating flow, high noise levels, lower efficiency and/or higher power consumption. Accordingly, it is generally desirable to operate the fan at air flow levels greater than those that would cause the fan to operate in the region. Said another way, referring the plot in
The plot in
The back pressure produced by the data processing unit and/or the air flow paths therein can be influenced by, among other things, the size (or flow area) of the air flow paths, the tortuosity of the air flow paths (i.e., the number and “sharpness” of the turns with the air flow paths) and/or the surface roughness of the components that define the air flow paths. Thus, system curve 274 can represent the air flow performance for a first data processing unit having larger and less tortuous air flow paths than that for a second data processing unit, which is represented by system curve 276. Because more pressure is used to produce a given air flow through the second data processing unit, the fan will be operating closer to the region of instability. As shown in
As shown in
This arrangement can allow the stator member 160 to be pre-selected, adjusted and/or optimized to produce the desired flow characteristics for a particular fan 110 within a particular air flow path 106 and/or data processing unit 100. For example, in some embodiments, a first data processing unit can include fewer rack units 104 than a second data processing unit, which can result in the first data processing unit having a less restrictive air flow path than the second data processing unit. Referring to the plot in
As another example, although the inlet air flow Vin shown in
Although the stator member 160 is shown as being on the intake side of the fan 110 (i.e., the inlet air first flows across the stator blades 164), in other embodiments, a fan tray assembly can include a stator member on the outlet side of a fan. For example,
In operation, an electric motor (not shown) produces energy to rotate the rotor 320 about the fan axis Af. The rotor blades 324 are aerodynamically designed to produce a pressurized air flow when the rotor 320 is rotated about the fan axis Af. More particularly, as shown in
The fan tray 343 can be any suitable structural member for supporting the fan 310 and coupling the fan tray assembly 340 within a data processing unit. In particular, the fan tray 343 defines an opening 342 corresponding to the fan 310. The fan 310 is coupled to the fan tray 343 such that the fan 310 and the opening 342 collectively define a portion of an air flow path 306 (shown in
The stator member 360 includes a set of stator blades 364 and is coupled to the fan tray 343 such that the fan 310 is disposed between the fan tray 343 and the stator member 360. The stator member 360 includes two mounting portions 363 to facilitate coupling the stator member 360 to the fan tray 343. The mounting portions can include any suitable features for coupling the stator member 360 to the fan tray 343, such as, for example, clips, bolt holes, adhesive or the like.
As shown in
In some embodiments, a stator member can be coupled to a fan tray such that the stator blades are disposed substantially within an opening defined by the fan tray. In this manner, the stator member can be coupled to the fan tray without significantly increasing the overall size and/or profile of the fan tray assembly. For example,
The fan 410 includes a housing 412, a rotor 420 and a motor 418 that is supported by struts 419. The rotor 420 has a set of rotor blades 424, and is configured to rotate about the fan axis Af to produce a pressurized air flow. More particularly, the rotor blades 424 are configured to produce an air flow in a direction substantially parallel to the fan axis Af, as shown by the arrow HH in
The fan tray 443 can be any suitable structural member for supporting the fan and coupling the fan tray assembly 440 within a data processing unit. The fan tray 443 defines an opening 442. The fan 410 is coupled to the fan tray 443 such that the fan 410 and the opening 442 collectively define a portion of an air flow path, similar to the air paths shown and described above. In this manner, cooling air can flow within the air flow path, as shown by the arrow HH, to facilitate cooling of the electronic devices contained within the data processing unit.
The stator member 460 includes a set of stator blades 464 and is coupled to the fan tray 443 such that the stator blades 464 are substantially within the opening 442. Similarly stated, the stator blades 464 are disposed within the opening 442 such that the stator blades 464 are substantially flush with or are recessed from a surface of the fan tray 443. Thus, the stator blades 464 are within the flow path such that the stator blades 464 and the rotor blades 424 can cooperatively produce a substantially axial air flow, as described above. Moreover, by having the stator blades 464 substantially within the opening 442, the clearance between the stator blades 464 and the rotor blades 424 can be reduced. This arrangement also allows for the improved fan performance via the stator blades 464 without significantly increasing the overall size of the fan tray assembly 440.
Although the stator members have been shown and described herein as being within and/or defining, at least in part, a substantially cylindrical air flow path, in other embodiments, a stator member can define a portion of an air flow path having any suitable shape. For example, in some embodiments, a stator member can define a portion of an air flow path having a substantially rectangular shape. In this manner, the shape of the air flow path can correspond to a shape of a line card or other electronic device within a rack unit (e.g., rack unit 104) and/or a data processing unit (e.g., data processing unit 100). In other embodiments, a stator member can define a portion of an air flow path that transitions from a substantially circular cross-sectional shape to a substantially rectangular cross-sectional shape. For example,
The stator member 560 can be coupled to and/or included within any of the fan tray assemblies shown and described herein. The stator member 560 includes a housing 561 defining a flow path 562 therein, and having an inlet portion 567 and an outlet portion 568. The inlet portion 567 includes a set of stator blades 564 that are disposed within the flow path 562. In this manner, air can flow across the stator blades 564 (e.g., after being acted upon by a fan rotor) and into the flow path 562, as shown by the arrow II in
As shown in
Although the fan tray assemblies, such as, for example, the fan tray assembly 140 are shown and described herein as including a fan tray (e.g., fan tray 143) and a separately constructed stator member (e.g., stator member 160), in other embodiments, the fan tray and the stator member can be monolithically constructed. Similarly stated, in some embodiments, the fan tray (i.e., the structural member to which one or more fans is mounted) and the stator blades can be constructed in the same operation or set of operations. For example, in some embodiments, the fan tray can be cast to include one or more sets of stator blades as shown above. In other embodiments, the fan tray can be molded (e.g., injection molded) to include one or more sets of stator blades as shown above.
Although the fan trays (e.g., fan tray 143) are shown and described herein as having a generally planar shape, in other embodiments, a fan tray assembly can be a rack unit having one or more fan trays having a non-planar and/or three-dimensional shape. For example,
The fan tray assembly 640 includes a base member 644 and a cover 645 that collectively define an interior region (not shown in
The cover 645 is monolithically constructed to include a set of stator blades 664 within each of the openings 643. The stator blades 664 can have a similar function and/or design as any of the stator blades shown and described above. Although not shown in
In some embodiments, a method of assembling a fan tray assembly includes coupling a stator member to a fan tray member independently from a fan being coupled to the fan tray member. The stator member can be any of the stator members shown and described herein, such as, for example, the stator member 160. In some embodiments, the method can further include coupling the fan to the stator member and/or the fan tray. The stator member can be coupled adjacent either the inlet portion of the fan or the outlet portion of the fan.
In some embodiments, a method can include monolithically constructing a fan tray member to include a set of stator blades of the types shown and described above. In some embodiments, the method further includes coupling one or more fans to the monolithically constructed fan tray member.
While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Where methods and/or schematics described above indicate certain events and/or flow patterns occurring in certain order, the ordering of certain events and/or flow patterns may be modified. While the embodiments have been particularly shown and described, it will be understood that various changes in form and details may be made.
The fans shown and described herein can be any suitable type of device for producing a pressurized air flow. For example, in some embodiments, a fan can be any suitable tubeaxial fan produced by Delta Electronics, Inc., such as for example, the QFR 60×60×38 Series tubeaxial fan. In other embodiments, a fan can be any suitable tubeaxial fan produced by EBM-Papst, Inc., such as for example, the 3000 Series tubeaxial fan. In yet other embodiments, a fan can be any suitable tubeaxial fan produced by the Nidec Servo Corporation, such as for example, the PUDC series tubeaxial fan. Moreover, although the fans are shown and described herein as being primarily tubeaxial fans, in other embodiments, a fan can be any suitable type of device for producing a pressurized air flow. For example, in some embodiments, a fan tray assembly can include centrifugal fans (i.e., blowers) or a combination of both axial fans and centrifugal fans.
Although air is the cooling medium described herein (e.g., the flow paths are often referred to as “air” flow paths), in other embodiments, any suitable gas can be used as the cooling medium. For example, in some embodiments, the cooing medium can be nitrogen.
Although the stator members shown and described above include a specific number of stator blades (e.g., the stator member 160 is shown as having five stator blades 164), in other embodiments, a stator member can have any suitable number of stator blades. In some embodiments, for example, a stator member can have the same number of stator blades as a number of rotor blades in the corresponding fan. In other embodiments, a stator member can have a fewer number of stator blades than a number of rotor blades in the corresponding fan. In yet other embodiments, a stator member can have a higher number of stator blades than a number of rotor blades in the corresponding fan.
Although the fan tray assemblies are shown as having one stator member for each fan, in other embodiments, a fan tray assembly can have any number of stator members and any number of fans. In some embodiments, a fan tray assembly can have more fans than stator members. For example, in some embodiments, a fan tray assembly can have one stator member having multiple sets of stator blades within multiple flow paths and/or redirecting flow from several fans. In other embodiments, a fan tray assembly can have fewer fans than stator members. In yet other embodiments, a fan tray assembly can include a first stator member on the inlet side of a fan and a second stator member on the outlet side of the fan.
Although various embodiments have been described as having particular features and/or combinations of components, other embodiments are possible having a combination of any features and/or components from any of embodiments as discussed above. For example, in some embodiments, rack-mountable fan tray assembly similar to the assembly shown in
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