MULTI-STAGE AIR MOVERS FOR COOLING
COMPUTER SYSTEMS AND FOR OTHER
TECHNICAL FIELD 5
The following disclosure relates generally to computer air conditioning systems and, more particularly, to air movers for use with such air conditioning systems.
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 15 a portion of a prior art supercomputer system 100 having plurality of computer cabinets 110 arranged in a bank. The computer cabinets 110 are arranged in a bank to conserve floor space and increase computational speed by reducing cable lengths between cabinets. Each of the computer cabi- 20 nets 110 includes a plurality of computer module compartments 118 (identified individually as a first module compartment 118a, a second module compartment 1186, and a third module compartment 118c). Each module compartment 118 holds a plurality of computer modules 112. Like the computer 25 cabinets 110, the computer modules 112 are also positioned in close proximity to each other to conserve space and increase computational speed. Each of the computer modules 112 can include a motherboard electrically connecting a plurality of processors, memory modules, routers, and other 30 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 35 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 modules 112, 40 the prior art supercomputer system 100 further includes a plurality of centrifugal fans 120 mounted to upper portions of corresponding computer cabinets 110. In operation, each of the centrifugal fans 120 draws cooling air into the corresponding computer cabinet 110 through a front inlet 114 45 and/or a back inlet 115 positioned toward a bottom portion of the computer cabinet 110. The cooling air flows upwardly through the computer cabinet 110, past the computer modules 112, and into a central inlet 122 of the fan 120. The centrifugal fan 120 then exhausts the cooling air outward in a radial 50 pattern through a circumferential outlet 124.
One problem associated with the prior art supercomputer system 100 is the inability of the centrifugal fan 120 to move a sufficient amount of air through the computer cabinet 110 for adequate cooling when the density of the computer mod- 55 ules 112 increases. As more computer modules 112 are installed in a given space (e.g., by decreasing the spacing between two adjacent computer modules 112), available flow paths for cooling air decrease, thereby increasing the pressure drop as the cooling air flows past the computer modules 112. 60 The centrifugal fan 120 typically 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 fan 120 increases the output pressure differential to compensate for the increased pressure drop, the 65 flow rate of the cooling air through the computer cabinet 110 is significantly reduced. The reduction in cooling air flow can
cause overheating of the computer modules 112, and thus adversely affect performance of the computer system 100.
Conventional techniques for increasing cooling air flow in densely packed computer cabinet 110 include increasing the size of the centrifugal fan 120 and increasing the operating speed of the centrifugal fan 120. There are a number of shortcomings associated with each of these solutions. First, increasing the size of the centrifugal fan 120 increases the power consumption of the centrifugal fan 120. In addition, the computer cabinet 110 may not have enough space to accommodate a fan 120 of increased size. Second, increasing the operating speed of the centrifugal fans 120 can cause a substantial increase in operating noise and power consumption.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a bank of computer cabinets having top-mounted cooling fans configured in accordance with the prior art.
FIG. 2 is a partially exploded isometric view of a computer cabinet having a plurality of multi-stage air movers configured in accordance with an embodiment of the invention.
FIG. 3 is an enlarged isometric view of an air mover assembly from the computer cabinet of FIG. 2.
FIG. 4 is an isometric view of a multi-stage air mover from FIGS. 2 and 3, configured in accordance with an embodiment of the invention.
FIG. 5 is a partially exploded isometric view of the multistage air mover of FIG. 4.
FIG. 6 is a side cross-sectional view illustrating one embodiment of the multi-stage air mover of FIG. 4.
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 assem