Plasma cooling heat sink
One embodiment of the present invention uses plasma-driven gas flow to cool down electronic devices. The cooling device comprises heat sink fin assembly, plasma actuator assembly, and magnetic circuit assembly. The plasma actuator assembly comprises electrodes and dielectric pieces. Voltages are applied to electrodes to drive the plasma gas flow. The magnetic circuit assembly provides magnetic field to interact with electrical field and plasma flow, and therefore an induced gas flow is pumped into, or pumped out from, heat sink fin assembly, to cool down heat sink fins.
This application is a Formal Application and claims priority to pending U.S. patent application 60/934,047 filed on Jun. 9, 2007 by the same Applicant of this Application, the benefit of its filing date being hereby claimed under Title 35 of the United States Code.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates generally to electronic equipment, and more particularly, to apparatus and methods for cooling electronic devices using plasma-driven gas flow.
2. Description of the Related Art
Electronic devices may generate significant heat during operation. High temperatures may reduce the lifespan of these devices, and, therefore, the generated heat may need to be dispersed to keep the operating temperature of the electronic devices within acceptable limits.
One commonly used cooling device is heat sink. Heat sinks may be coupled to electronic devices to absorb heat through the heat sink base and disperse the heat through their fins. Conventional methods to disperse the heat through the heat sink fins are natural convection and forced convection. Natural convection is to disperse the heat away from the surfaces of heat sink fins without the aid of external forced fluid pumping through heat sink fins. On the other hand, the forced convection cooling is to pump the fluid to flow through heat sink fins, such as the fans to blow the air through the heat sink fins, and therefore enhance the heat transfer between fins and outside ambient.
With the increasing power density of electronic devices, the pitch or the distance between heat sink fins is becoming smaller, which means more surface area may be used to transport the heat away. However, when the pitch becomes very small, the pressure drop between inlet and outlet of the heat sink fins may become very high, which may results the difficulties to pump the fluid flowing through fins, and as a result, more powerful fans, which consume higher electricity may be needed for the cooling. The invention utilizes plasma-driven gas flow to conduct the convective heat transfer along the heat sink fins and therefore will resolve these issues.
Another consideration of the electronic device cooling is that, due to size concern, the internal space allowed to put cooling fans and other cooling components, may be limited or not permitted. The invention utilizes the plasma-driven gas flow to generate the forced convective heat transfer on the heat sink fins, and hence, is able to improve the heat transfer efficiency and to minimize the required space because some cooling components are assembled inside heat sink fins.
Another aspect of using the invention is to lower the required power of the system fans of electronic devices. The plasma driven gas flow on the heat sink fins will induce the local turbulence on the heat sink surfaces. Higher momentum of the fluid is obtained and the cooling is achieved. Therefore, in this way, the system fan doesn't need to be very powerful in order to cool down heat source.
Plasma-driven gas flow has been used either to cool articles or to control and modify the fluid dynamics boundary layer on the wings surfaces of the aerodynamic vehicles. For example, U.S. Pat. No. 3,938,345 used the phenomenon of corona discharge, which is one type of plasma, to do the local cooling of an article. U.S. Pat. No. 4,210,847 designed an apparatus for generating an air jet for cooling application. U.S. Pat. No. 5,554,344 had a gas ionization device to do the cooling of zone producing chamber. U.S. Pat. No. 6,796,532 B2 used a plasma discharge to manipulate the boundary layer and the angular locations of its separation points in cross flow planes to control the symmetry or asymmetry of the vortex pattern.
However, none of the above patents are coupled to the heat sink, which is a fundamental apparatus for cooling electronic devices. Hence, what are needed are a method and an apparatus, to couple with heat sink fins to cool down electronic devices efficiently.
SUMMARY OF THE INVENTIONOne embodiment of the present invention provides a plasma-driven cooling device couple to heat sink fins to induce the gas flow along the heat sink fins. The induced gas flow will remove the heat away from heat sink fin surface and therefore the heat source is cool down.
In one embodiment, the plasma-driven cooling device includes heat sink fin assembly, magnetic circuit assembly, and plasma actuator assembly. The heat sink fin assembly includes a plurality of heat sink fins. The magnetic circuit assembly includes ferromagnetic yokes and magnets. The plasma actuator assembly includes electrodes and dielectric pieces.
In one embodiment, each plasma actuator in the plasma actuator assembly may be separately controlled and powered, such as, by a controller and a power supplier, to provide different convective cooling rates at different locations on the heat sink fins.
In one embodiment, plasma-driven gas may flow in varied directions and the flow patterns may vary. The electrodes, heat sink fins, and dielectric pieces may have varied configurations and geometry.
In one embodiment, varied voltages may be applied to the electrodes to induce the gas flow to cool down the heat source. The applied voltages may have varied waveforms, frequencies, amplitude, phase shifts, and time period.
In one embodiment, the magnetic circuit assembly may have different configurations to provide magnetic field. The magnetic field will interact with electrical field and plasma to induce turbulent flow, and therefore, the heat source is cooled down.
In one embodiment, the electrodes may be populated in between heat sink fins, and when the voltages are applied to these electrodes, the induced ions gas flow may cool down the heat sink assembly.
In one embodiment, the sharp electrodes may be made along out-of-plane or in-plane direction.
In one embodiment, the plasma actuators may be populated in between heat sink fins, at the entrance of the heat sink fins, or at any locations to couple with heat sink fins assembly.
In one embodiment, the electrode traces may be layout with varied configurations and the sharp electrodes may be populated on the electrode traces.
A better understanding of the present invention may be obtained when the following detailed description is considered in conjunction with the following drawings, in which:
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. Furthermore, note that the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not a mandatory sense (i.e., must). The term “include”, and derivations thereof, mean “including, but not limited to”. The term “coupled” means “directly or indirectly connected”.
DETAILED DESCRIPTION OF THE INVENTIONThe invention generally relates to apparatus for cooling microelectronic devices or packages, such as microprocessors, and ASIC. Such systems and methods may be used in a variety of applications. A non-exhaustive list of such applications includes the cooling of: a microprocessor chip, a graphics processor chip, an ASIC chip, a video processor chip, a DSP chip, a memory chip, a hard disk drive, a graphic card, a portable testing electronics, a personal computer system.
Take laptop computer for example, conventional fans use a lot of space and energy. For this reason, the plasma-driven cooling device represents a way to increase their cooling capacity and make them more reliable and far quieter. Therefore the higher-performance chips that generate too much heat for current laptops can be used.
As used herein “plasma” is an ionized gas, a gas into which sufficient energy is provided to free electrons from atoms or molecules and to allow both species, ions and electrons, to coexist. Plasma is even common here on earth. A plasma is a gas that has been energized to the point that some of the electrons break free from, but travel with, their nucleus. Gases can become plasmas in several ways, but all include pumping the gas with energy. A spark in a gas will create a plasma. A hot gas passing through a big spark will turn the gas stream into a plasma that can be useful. Plasma torches like that are used in industry to cut metals.
As used herein “electrode” is an electrical conductor used to make contact with a metallic part of a circuit.
As used herein “dielectric piece” is a substance that is a poor conductor of electricity, but an efficient supporter of electrostatic fields. In practice, most dielectric materials are solid. An important property of a dielectric is its ability to support an electrostatic field while dissipating minimal energy in the form of heat. The lower the dielectric loss (the proportion of energy lost as heat), the more effective is a dielectric material. Another consideration is the dielectric constant, the extent to which a substance concentrates the electrostatic lines of flux. Substances with a low dielectric constant include a perfect vacuum, dry air, and most pure, dry gases such as helium and nitrogen. Materials with moderate dielectric constants include ceramics, distilled water, paper, mica, polyethylene, and glass. Metal oxides, in general, have high dielectric constants.
In one embodiment, the plasma actuator assembly 106 and heat sink fin assembly 104 may have varied configurations.
The magnetic field will interact with electrical field and plasma field to induce the gas flow.
To couple the magnetic field with ions flow is one way of doing the cooling. However, using pure electrostatic or electro-dynamic field without magnetic field is sometimes more straightforward and
In
Therefore, this invention discloses a method and apparatus for cooling electronic devices. The method and apparatus includes a plurality of heat sink fins forming a heat sink fin assembly, a magnetic circuit assembly and a plasma actuator assembly. In one exemplary embodiment, the magnetic circuit assembly and plasma actuator are coupled to heat sink fin assembly, and the magnetic circuit assembly and plasma actuator assembly may be at the inlet, outlet, or any locations of the heat sink fin assembly. In another exemplary embodiment, the plasma actuator assembly includes a plurality of plasma actuators, and plasma actuators include electrodes and dielectric pieces. In another exemplary embodiment, appropriate voltages can be applied to the electrodes on the plasma actuators to induce a gas to flow into or to flow out of heat sink fin assembly, and therefore remove the heat from heat sink fins surface. In another exemplary embodiment, the applied voltages to electrodes can be DC or AC, steady or transient, fixed or varied amplitude, fixed or varied frequency, with or without phase shift difference, and may have different waveforms. In another exemplary embodiment, the plasma actuator assembly may be powered and controlled by power suppliers and controllers, and all plasma actuators on the plasma actuator assembly may be powered all together, or each plasma actuator on the plasma actuator assembly may be powered and controlled individually, to cool down the heat sink fin assembly. In another exemplary embodiment, the electrodes may have varied patterns, and the patterns may have varied geometry, and the relative relocations among electrodes and patterns may be varied. In another exemplary embodiment, the heat sink fin assembly and plasma actuator assembly may have varied configurations; and the configurations may be used, to push the gas into heat sink fin assembly. In another exemplary embodiment, the applied voltages on the electrodes may be arranged to induce a traveling plasma wave, and the traveling plasma wave may be used to push the gas into heat sink fin assembly, and to push the gas out from heat sink fin assembly. In another exemplary embodiment, the magnetic circuit assembly includes yokes and magnets, and the yokes and magnets may have varied configurations. In another exemplary embodiment, the yokes and magnets may have varied geometry, varied grade, varied materials compositions, varied magnetization orientation, and varied relative locations. In another exemplary embodiment, the cooling apparatus may couple to heat source directly, or couple to heat source through heat transferring pipes and attachment components. In another exemplary embodiment, the transferring pipe may be heat pipe, liquid cooling pipe, refrigeration cooling pipe, or other heat-transferring pipe. In another exemplary embodiment, the apparatus further comprises thermal sensors coupled to heat sink fin assembly, wherein the thermal sensors are operable to measure the temperatures on heat sink fin assembly, and based on the measured temperatures, the power supplier and controller can command plasma actuators to adjust the cooling rate accordingly. In another exemplary embodiment, the magnetic circuit assembly is to provide a magnetic field, and wherein the magnetic circuit can be made of permanent magnets or electromagnets. In another exemplary embodiment, the heat source can include a microprocessor chip package; a graphics processor chip package; an ASIC chip package; a video processor chip package; a DSP chip package; a memory chip package; a hard disk drive; a power supply; or a graphic card; and any other heat sources within the electronic system. In another exemplary embodiment, the gas can include plasma, air, nitrogen, oxygen, and other fluids. In another exemplary embodiment, the dielectric material can include air, vacuum, Teflon, Kapton, and other materials. In another exemplary embodiment, the electrodes material can include gold, copper, nickel, tungsten, and other electrically conductive materials. In another exemplary embodiment, the heat sink fin assembly and plasma actuator assembly may be manufactured with different scale, such as, a bulk scale, a micro-scale, or a nano-micrometer scale.
Although the present invention has been described in terms of the presently preferred embodiment, it is to be understood that such disclosure is not to be interpreted as limiting. Various alternations and modifications will no doubt become apparent to those skilled in the art after reading the above disclosure. Accordingly, it is intended that the appended claims be interpreted as covering all alternations and modifications as fall within the true spirit and scope of the invention.
Claims
1. A method and apparatus for cooling electronic devices, comprising:
- a plurality of heat sink fins forming a heat sink fin assembly;
- a magnetic circuit assembly;
- a plasma actuator assembly;
2. The cooling device of claim 1, wherein the magnetic circuit assembly and plasma actuator are coupled to heat sink fin assembly, and the magnetic circuit assembly and plasma actuator assembly may be at the inlet, outlet, or any locations of the heat sink fin assembly;
3. The cooling device of claim 1, wherein the plasma actuator assembly comprising a plurality of plasma actuators, and plasma actuators comprising electrodes and dielectric pieces;
4. The cooling device of claim 3, appropriate voltages can be applied to the electrodes on the plasma actuators to induce a gas to flow into or to flow out of heat sink fin assembly, and therefore remove the heat from heat sink fins surface;
5. The cooling device of claim 4, wherein the applied voltages to electrodes can be DC or AC, steady or transient, fixed or varied amplitude, fixed or varied frequency, with or without phase shift difference, and may have different waveforms;
6. The cooling device of claim 1, wherein the plasma actuator assembly may be powered and controlled by power suppliers and controllers, and all plasma actuators on the plasma actuator assembly may be powered all together, or each plasma actuator on the plasma actuator assembly may be powered and controlled individually, to cool down the heat sink fin assembly;
7. The cooling device of claim 3, wherein the electrodes may have varied patterns, and the patterns may have varied geometry, and the relative relocations among electrodes and patterns may be varied;
8. The cooling device of claim 1, wherein the heat sink fin assembly and plasma actuator assembly may have varied configurations; and the configurations may be used, to push the gas into heat sink fin assembly;
9. The cooling device of claim 5, wherein the applied voltages on the electrodes may be arranged to induce a traveling plasma wave, and the traveling plasma wave may be used to push the gas into heat sink fin assembly, and to push the gas out from heat sink fin assembly;
10. The cooling device of claim 1, wherein the magnetic circuit assembly comprising yokes and magnets, and the yokes and magnets may have varied configurations;
11. The cooling device of claim 10, wherein the yokes and magnets may have varied geometry, varied grade, varied materials compositions, varied magnetization orientation, and varied relative locations;
12. The cooling device of claim 1, wherein the cooling apparatus may couple to heat source directly, or couple to heat source through heat transferring pipes and attachment components;
13. The cooling device of claim 12, wherein the transferring pipe may be heat pipe, liquid cooling pipe, refrigeration cooling pipe, or other heat transferring pipe;
14. The cooling device of claim 1, further may comprises thermal sensors coupled to heat sink fin assembly, wherein the thermal sensors are operable to measure the temperatures on heat sink fin assembly, and based on the measured temperatures, the power supplier and controller can command plasma actuators to adjust the cooling rate accordingly;
15. The cooling device of claim 1, wherein the magnetic circuit assembly is to provide a magnetic field, and wherein the magnetic circuit can be made of permanent magnets or electromagnets;
16. The apparatus for cooling an electronic device of claim 1, wherein the plasma actuator assembly may comprise a plurality of electrode traces populated on a dielectric layer and couple to a heat sink base.
17. The apparatus for cooling an electronic device of claim 16, wherein the electrode traces may have sharp electrodes populated on them.
18. The apparatus for cooling an electronic device of claim 16, the voltages applied to the electrode traces may be varied to induce the ions flow to flow in-plane and out-of-plane directions, and therefore cooling down the heat source.
19. The apparatus for cooling an electronic device of claim 16, wherein the electrode traces may be located at the entrance, at the exit, or at any location inside the heat sink assembly.
20. The apparatus for cooling an electronic device of claim 16, the heat sink fins may have varied configurations, and the electrode traces may have varied layout populated on the dielectric layer.
Type: Application
Filed: Jun 8, 2008
Publication Date: Dec 11, 2008
Inventor: Chien Ouyang (Sunnyvale, CA)
Application Number: 12/157,233
International Classification: F28D 15/00 (20060101);