Patent Grant
7021891
The present invention relates to fluid handling equipment, and more particularly, to a centrifugal compressor including a micro-impeller for the cooling of electronic devices.
Certain electronic devices can generate a significant amount of heat. This heat must be removed from the device to prevent overheating leading to failure of the device. With current trends for increasingly smaller electronic devices, there is a need for smaller cooling systems.
One approach used in the art relies on miniaturizing large industrial/residential compressors such as reciprocating (piston) or rotary compressors. These systems work well for their current applications, but have limited application for sensitive electronic equipment because of there inherent large vibrational forces and power requirements. These compressors rely on positive displacement, such as a moving piston or rotary vane, and intermittent operation, to compress the working fluid, which is commonly a gas.
Electronic cooling units must be designed to a unique set of conditions that yield a narrow operating range for the electronic device's volumetric flow rate capacity. This translates into little flexibility for future applications, as any further increase in cooling needs is likely to restrict the operating range of the electronic device or push it out of specification.
Electronic devices found in advanced computing devices require stringent thermal-management needs. Specifically, the ever-increasing power dissipation needs of microprocessors found in advanced electronic devices and systems are quickly approaching available cooling system limits of volumetric flow rate needed for cooling beyond the operating range of existing systems.
New fluid handling systems for cooling of electronic devices are needed not only for the needs of future electronic devices, but to provide more efficient systems for current devices. They must provide for exceptionally small-scale integration, not interfere with the electrical interface of other components within the microelectronic package, and inexpensive to manufacture.
In the following detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals designate like parts throughout, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.
An impeller in accordance with the present invention operates in a compressor and has blade geometry suited to impel high velocity to gas molecules to produce a high discharge pressure.
In operation, the compressor 10 draws the working fluid into the housing 12 through the inlet aperture 20 by vacuum created by the rotation of the micro-impeller 14. The fluid passes through the micro-impeller 14 which compresses the fluid and expels the fluid out of the outlet aperture 24 under high pressure.
The compressor 10 is adapted for, but not limited to, use in a refrigeration cycle as part of a cooling system for high performance computing platforms.
The back-to-back micro-impeller 114 provides a fluid path on both sides 32 of the micro-impeller 114, imparting an equal momentum (or velocity) to the fluid. This provides an equal force loading on each side of the micro-impeller 114 which reduces frictional and vibration forces as compared with single-sided impellers.
Also, the approximately equally distributed mass about the rotation axis X, provides for a balanced rotor, defined as the back-to-back micro-impeller 114 and shaft 16, which is desirable when operated at high revolutions-per-minute (RPM).
The back-to-back micro-impeller 114 comprises a plurality of spaced-apart blades 34 that extend from a base plate 36 (also referred herein as a disk) a predetermined distance. The blades 34 are geometrically varied so that the most efficient transfer of energy from the blades 34 to the working fluid is achieved. The design of the blades 34 depends on the efficiencies and pressure rise required of the compressor 10.
The blades 34 radiate from proximate the shaft 16 to the outer edge 40 or proximate the outer edge 40 of the base plate 36. The blades 34 are spaced-apart from the shaft a predetermined distance defining an impeller inlet 38. The working fluid enters the micro-impeller 114 at the impeller inlet 38 and exits proximate the outer edge 40 of the base plate 36.
In another embodiment of the micro-impeller (not shown) in accordance with the present invention, the blades twist as they radiate out to the outside diameter of the impeller. Twist is defined as a continuous change in the angle of the blade to the base plate as a factor of a change in the distance from the shaft. A blade that twists is referred to as being 3D, whereas one that does not twist and simply extends perpendicular to the base plate regardless of distance from the shaft is referred to as being 2-D.
The micro-impeller 114 comprises a base plate 36 from which the blades 34 extend. The blades 34 can be coupled to the base plate 36 using common processes, such as, but not limited to, welding, and milling from a solid billet. The blades 34 must be able to withstand the forces required to convert the torque from the shaft 16 to the working fluid as well as the centrifugal forces at the blade tips and base plate outer edge 40.
In another embodiment in accordance with the present invention, the back-to-back micro-impeller 114 is a component of a single stage compressor 10. A stage is defined as one compression region, whereas a two stage compressor will have two compression regions connected in series.
In another embodiment in accordance with the present invention, the back-to-back micro-impeller 114 is a component of a multiple stage compressor (not shown). The choice between compressor designs depends on the pressure ratio required and the thermodynamic state desired of the working fluid during the compression cycle. This flexibility provides that the micro-impeller 114 in accordance with the invention can be designed for many different applications.
Referring to
The benefit of having a left compressor section 13 and a right compressor section 11 is that there is a balancing of forces generated by high-pressure fluid against the two sides 32 of the micro-impeller 114. This reduces vibrational forces as well as provides a balancing force on the shaft 16 which reduces the thrust on the shaft 16 in a direction away from the gas flow path.
The material from which the micro-impeller 114 is made should be capable of taking the form of the micro-impeller 114, and being durable and corrosion resistant to the working fluid. A suitable material for many applications is aluminum, but the micro-impeller 114 is not limited only to aluminum. Other materials include other metals and plastics.
One benefit of a compressor 10 comprising a micro-impeller 114 is that there is small deviation in discharge pressure for a given change in volumetric flow rate. The compressor 10 can deliver relative large volumetric flow range (−65%–120% of flow capacity) over a relatively minor change in output discharge pressure.
An embodiment of the back-to-back micro-impeller compressor 10 in accordance with
In other embodiments in accordance with the present invention, the back-to-back micro-impeller is a component of a compressor having an outlet aperture. The compressor is collocated with at least one electronic component of a microelectronic system such that the outlet aperture is located proximate the at least one electronic component. Examples of a microelectronic system include, but not limited to: a microelectronic package, such as, but not limited to a microprocessor; a microelectronic circuit board, such as, but not limited to a computer memory and/or video card; and an electronic component within an electronic housing, such as, but not limited to, a power supply and/or a disk drive housed within a computer enclosure.
Although specific embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent implementations calculated to achieve the same purposes may be substituted for the specific embodiment shown and described without departing from the scope of the present invention. Those with skill in the art will readily appreciate that the present invention may be implemented in a very wide variety of embodiments. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that this invention be limited only by the claims and the equivalents thereof.
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| Number | Date | Country | |
|---|---|---|---|
| 20040120802 A1 | Jun 2004 | US |
