CN102620590A - Micro-channel heat sink and performance testing device thereof - Google Patents

Abstract

A microchannel heat sink utilizing hydrodynamic cavitation to enhance heat exchange mainly includes: a microchannel plate, a fluid inlet, an inlet pressure measurement port, a cavitation generator, a mainstream microchannel, Outlet pressure measurement port and fluid outlet; cavitation generators are arranged at intervals along the liquid flow direction in the main flow microchannel, and the width ratio between the cavitation generator and the main flow microchannel is 0.1 to 0.6; a sealing cover plate is set On the plane of the microchannel plate, the sealing cover plate is provided with a fluid inlet, an inlet pressure measurement port, an outlet pressure measurement port and a fluid outlet, respectively corresponding to the fluid inlet, inlet pressure measurement port, outlet pressure measurement port and Fluid outlet; a heating element, located on the other plane of the microchannel plate. The invention also discloses a performance testing device for the microchannel heat sink.

Description

A microchannel heat sink and a performance testing device for the microchannel heat sink

technical field

The invention belongs to the technical field of high-efficiency cooling, and in particular relates to a microchannel heat sink which utilizes hydraulic cavitation to enhance heat exchange.

The invention also relates to a device for testing the performance of the microchannel heat sink.

Background technique

The concept of microchannel heat sink was first proposed by American scholars Tuckerman and Pease in the 1980s. The microchannel heat sink is small in size and compact in structure, and its channel size can reach the order of tens or even several microns, so it can directly act on the position of the heat source in a small space. With its high-efficiency cooling capacity, simple cooling structure and good compatibility, micro-channel heat sink has become the most promising high-efficiency cooling method in the microelectronics industry. However, with the rapid increase in the operating frequency of high-performance integrated devices, their power density has risen sharply. At present, high-performance CPUs are close to the power density of nuclear reactors, and the power densities of high-power devices (such as IGBTs) and laser diode (DL) arrays have reached hundreds of watts, or even kilowatts. Under normal working conditions, the heat consumption in these devices accounts for more than 50% of the total power. In order to ensure the performance of the devices, this part of the heat must be taken away in time. Faced with such a high heat flux density, the cooling capacity of traditional microchannel heat sinks can no longer meet the development requirements of high-performance electronic components. Timely elimination of waste heat due to power dissipation in a limited space has become a constraint for high-power integrated circuit technology and The main bottleneck in the development of laser technology, there is an urgent need to research and develop new cooling technologies and methods with high-density heat dissipation capabilities.

Cavitation refers to the process of formation, growth and collapse of vapor or gas cavities in a liquid or on a liquid-solid interface when the local pressure inside the liquid is reduced. Hydraulic cavitation, as the name implies, realizes the cavitation of liquid through a certain hydraulic structure. When the fluid flows through the hydraulic structure, due to the flow limiting effect of the hydraulic structure, its flow rate rises sharply. As a price, its pressure drops sharply. When the pressure drops to the working Cavitation occurs when the saturated vapor pressure of the liquid is lower than the temperature. Previous studies have shown that high-density energy of 1-10 ¹⁸ Kw/m ³ can be formed when cavitation bubbles collapse, which can be used as energy input for physical/chemical processes to achieve the purpose of strengthening the process. At present, hydraulic cavitation technology has been widely used in chemical industry, drinking water disinfection and wastewater treatment and other fields.

When the cavitation bubble collapses, a strong shock wave and high-speed micro-jet will be formed, which can not only disturb the liquid flow, but also cause a change in the liquid flow pattern, thereby achieving the purpose of enhancing heat transfer. Therefore, hydraulic cavitation is introduced into the microchannel The heat sink structure can greatly improve the cooling capacity of the microchannel heat sink to meet the requirements of the rapid development of high-power integrated circuit technology and laser technology.

Contents of the invention

The object of the present invention is to provide a micro-channel heat sink that utilizes hydraulic cavitation to enhance heat exchange.

Another object of the present invention is to provide a device for testing the performance of the above-mentioned microchannel heat sink.

In order to achieve the above purpose, the microchannel heat sink that utilizes hydraulic cavitation to enhance heat exchange provided by the present invention mainly includes:

A microchannel plate, a plane of the microchannel plate is provided with a fluid inlet, an inlet pressure measurement port, a cavitation generator, a mainstream microchannel, an outlet pressure measurement port and a fluid outlet;

Cavitation generators are arranged at intervals (equal or unequal intervals) along the liquid flow direction in the main flow microchannel, and the width ratio between the cavitation generator and the main flow microchannel is 0.1 to 0.6;

A sealing cover plate is arranged on the plane of the microchannel plate, and the sealing cover plate is provided with a fluid inlet, an inlet pressure measurement port, an outlet pressure measurement port and a fluid outlet, respectively corresponding to the fluid inlet and inlet pressure measurement ports opened on the microchannel plate , outlet pressure measurement port and fluid outlet;

A heating element is arranged on the other plane of the microchannel plate.

The microchannel heat sink, wherein the material of the microchannel plate is silicon, stainless steel, copper or other metal alloys.

The microchannel heat sink, wherein the material of the sealing cover plate is silicon, stainless steel, copper or heat-resistant transparent glass.

In the microchannel heat sink, there is a flow distribution chamber between the fluid inlet of the microchannel plate and the main flow microchannel, and a fluid collection chamber between the main flow microchannel and the fluid outlet.

Described microchannel heat sink, wherein, the cross-section of the cavitation generator in the microchannel plate and the mainstream microchannel is square, circular, triangular, trapezoidal or polygonal, the equivalent of both the cavitation generator and the mainstream microchannel The diameter ratio is 0.2-0.7.

In the microchannel heat sink, the number of the main microchannels is determined according to the heating area of the heating element.

The device for measuring the performance of the above-mentioned microchannel heat sink provided by the present invention includes:

The fluid inlet of the micro-channel heat sink is connected to a liquid storage tank through a power pump, and the fluid outlet of the micro-channel heat sink is connected to a cooler through a flow meter, and the cooler is connected to the liquid storage tank to make the liquid in the liquid storage tank form a cycle ;

The fluid inlet and the fluid outlet of the microchannel heat sink are respectively connected with a thermocouple, and the liquid temperatures of the fluid inlet and the fluid outlet of the microchannel heat sink are respectively measured;

The heating element of the microchannel plate is connected with a thermocouple to measure the temperature of the heating wall;

The inlet pressure measurement port and the outlet pressure measurement port of the microchannel heat sink are respectively connected with pressure sensors to measure the inlet pressure and outlet pressure of the microchannel heat sink.

The device, wherein a valve is installed between the fluid inlet of the microchannel heat sink and the liquid storage tank, and between the fluid outlet of the microchannel heat sink and the flowmeter, to adjust the fluid inlet and fluid flow of the microchannel heat sink. The outlet pressure reaches the condition of liquid cavitation.

Said device, wherein, the flow meter, the thermocouple and the pressure sensor are all connected to the data acquisition system, and processed and analyzed by the computer.

The invention introduces the hydraulic cavitation phenomenon into the micro-channel heat sink, and can greatly improve the cooling capacity of the micro-channel heat sink without adding other equipment.

Description of drawings

Fig. 1 is a three-dimensional schematic diagram of a microchannel heat sink used in an embodiment of the present invention.

FIG. 2 is a schematic diagram of a three-dimensional package of the microchannel heat sink shown in FIG. 1 .

Fig. 3 is a three-dimensional schematic diagram of a microchannel plate.

Fig. 4 is a schematic diagram of the microchannel heat sink performance testing device of the present invention.

Detailed ways

The microchannel heat sink of the present invention comprises: a heating element 1 , a microchannel plate 2 and a sealing cover plate 3 .

In the microchannel heat sink of the present invention, the material of the microchannel plate 2 can be silicon, stainless steel, copper or other metal alloys.

In the microchannel heat sink of the present invention, the microchannel plate 2 includes: a fluid inlet 4 , an inlet pressure measurement port 5 , a cavitation generator 6 , a mainstream microchannel 7 , an outlet pressure measurement port 8 and a fluid outlet 9 .

In the microchannel heat sink of the present invention, there is a flow distribution chamber A between the fluid inlet 4 and the main flow microchannel 7 , and a fluid collection chamber B between the main flow microchannel 7 and the fluid outlet 9 .

In the microchannel heat sink of the present invention, cavitation generators 6 are arranged at intervals along the liquid flow direction in the main flow microchannel, and the cavitation generators 6 can be arranged at equal intervals, or at unequal intervals (that is, not at equal intervals) regularity) arrangement. The width ratio (h/H) between the cavitation generator 6 and the main microchannel 7 ranges from 0.1 to 0.6.

In the microchannel heat sink of the present invention, the cross section of the cavitation generator 6 and the mainstream microchannel 7 can be square, circular, triangular, trapezoidal or polygonal, and the equivalent diameter ratio of the two is in the range of 0.2-0.7.

In the microchannel heat sink of the present invention, the sealing cover plate 3 is composed of a fluid inlet 4, an inlet pressure measurement port 5, an outlet pressure measurement port 8 and a fluid outlet 9, and its material can be silicon, stainless steel, copper or heat-resistant transparent glass.

The microchannel heat sink performance testing device of the present invention comprises: microchannel heat sink, liquid storage tank 10, power pump 11, valve 12 and 18, thermocouple 13, 15 and 17, pressure measuring sensor 14 and 16, flowmeter 19, Chiller 20, data acquisition system 21 and computer 22.

In the testing device of the present invention, thermocouple 13 and 17 are installed in the fluid inlet and the fluid outlet of microchannel heat sink, measure the temperature of microchannel heat sink inlet and outlet place fluid respectively; Thermocouple 15 is installed in the microchannel plate 2 back The surface of the heating element used to measure the temperature of the heating wall.

In the test device of the present invention, the pressure sensor 14 is installed on the inlet pressure measurement port 5 of the microchannel heat sink, and the pressure sensor 16 is installed on the outlet pressure measurement port 8 of the microchannel heat sink.

In the test device of the present invention, the valve 12 is installed between the fluid inlet of the power pump 11 and the microchannel heat sink, and the valve 18 is installed downstream of the fluid outlet of the microchannel heat sink. By cooperating with the regulating valves 12 and 18, the micro The pressure of the fluid inlet and outlet of the channel heat sink to achieve the condition of liquid cavitation.

In the test device of the present invention, the cooler 20 is installed downstream of the microchannel heat sink to keep the temperature of the fluid entering the microchannel heat sink constant.

In the test device of the present invention, all temperature signals, pressure signals and flow signals are collected by the data collection system 21 to the computer 22 for processing and analysis.

The present invention will be described in detail below in conjunction with the accompanying drawings.

Please refer to Figures 1 to 3, the cooling liquid medium enters the microchannel plate through the fluid inlet 4, and the cooling liquid is evenly distributed to each mainstream microchannel 7 through the flow distribution cavity A, in the microchannel heat sink of the present invention , the number of mainstream microchannels 7 can be determined according to the heating area of the heating element 1, and is not limited to the values shown in the figure.

In the main flow microchannel 7, cavitation generators 6 are arranged at intervals along the liquid flow direction. Since the cross section of the cavitation generator 6 is much smaller than the cross section of the main flow microchannel 7, the liquid flows through the cavitation generators. At 6 o'clock, its flow rate rises sharply, and its pressure drops sharply as a price, thereby generating cavitation bubbles. When the liquid flows out of the cavitation generator 6 and re-enters the mainstream microchannel 7, the liquid pressure begins to recover, and the cavitation bubbles begin to collapse, forming a high-speed microjet that impacts the bottom and both sides of the mainstream microchannel 7, thereby strengthening The role of heat transfer. Since a plurality of cavitation generators are arranged in the flow direction of the mainstream microchannel 7, cavitation bubbles are continuously formed and collapsed, so that the heat transfer capability of the entire cooling wall surface is greatly improved. After the liquid flows through the cooling channel, it is collected in the fluid collection cavity B, and then flows out through the fluid outlet 9 to complete the cooling of the heating element.

As shown in Figure 4, microchannel heat sink performance testing device of the present invention is made of microchannel heat sink, liquid storage tank 10, power pump 11, valve 12 and 18, thermocouple 13, 15 and 17, pressure measuring sensor 14 and 16 , flow meter 19, cooler 20, data acquisition system 21 and computer 22. The circulating power of the cooling liquid medium is provided by the power pump 11. After the cooling liquid comes out of the liquid storage tank 10, it passes through the control valve 12, and then enters the microchannel heat sink through the fluid inlet 4 to cool the heating element. 9 outflow microchannel heat sink. In order to accurately measure the heat transfer capability of the microchannel heat sink, the temperature of the liquid at the fluid inlet of the microchannel heat sink must be kept constant. Therefore, the cooled liquid must be cooled by the cooler 20 and then re-enter the liquid storage tank 10 . The pressure sensors 14 and 16 arranged on the inlet pressure measurement port 5 and the outlet pressure measurement port 8 can measure the liquid pressure at the inlet and outlet of the microchannel heat sink, thereby judging the liquid cavitation in the microchannel heat sink. The control of the liquid pressure at the inlet and outlet of the microchannel heat sink can be realized by adjusting the valves 12 and 18 . Through the thermocouples 13, 15 and 17 arranged at the fluid inlet and fluid outlet of the microchannel heat sink and the heating wall, the temperature of the liquid in the microchannel heat sink and the temperature of the heating wall can be measured. The flow rate of the cooling liquid in the circulation loop is measured by a flow meter 19 . All temperature signals, pressure signals and flow signals are collected by the data acquisition system 21 to the computer 22 for processing and analysis. The average heat transfer coefficient h of the microchannel heat sink is obtained by the following formula:

$\stackrel{<span\; class="notranslate">\; \&OverBar;</span>}{\mathrm{<span\; class="notranslate">\; h</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; q</span>}}{\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span>\mathrm{<span\; class="notranslate">\; \&Delta;t</span>}}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; c</span>}}_{\mathrm{<span\; class="notranslate">\; p</span>}}\mathrm{<span\; class="notranslate">\; \&rho;Q</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; -</span>\frac{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span>}$

In the above formula, q is the heat flux density, Δt is the average heat transfer temperature difference, c _p is the specific heat of the cooling liquid at constant pressure, ρ is the density of the cooling liquid, Q is the circulating flow rate of the cooling liquid, A is the heat transfer area, and t _w is the wall temperature , t _f1 is the fluid inlet liquid temperature of the microchannel heat sink, and t _f2 is the fluid outlet liquid temperature of the microchannel heat sink.

Claims (10)

1. micro-channel heat sink that utilizes the Hydrodynamic cavitation enhanced heat exchange mainly comprises:

One microchannel is dull and stereotyped, offers fluid intake, inlet pressure measurement port, cavitation generator, main flow microchannel, outlet pressure measurement port and fluid issuing on the plane of this microchannel flat board;

In the main flow microchannel, be provided with the cavitation generator along the liquid flow direction compartment of terrain, the width ratio between cavitation generator and the main flow microchannel is 0.1～0.6;

One seal cover board; Be located on the dull and stereotyped plane, this microchannel; Seal cover board is provided with fluid intake, inlet pressure measurement port, outlet pressure measurement port and fluid issuing, the fluid intake that corresponding respectively microchannel flat board is offered, inlet pressure measurement port, outlet pressure measurement port and fluid issuing;

One heater element is located at another dull and stereotyped plane of microchannel.

2. micro-channel heat sink as claimed in claim 1, wherein, the dull and stereotyped material in microchannel is silicon, stainless steel, copper or other metal alloy.

3. micro-channel heat sink as claimed in claim 1, wherein, the material of seal cover board is silicon, stainless steel, copper or heatproof clear glass.

4. micro-channel heat sink as claimed in claim 1 wherein, has a flow distribution cavity between fluid intake that the microchannel is dull and stereotyped and the main flow microchannel, and a fluid collection chamber is arranged between main flow microchannel and fluid issuing.

5. micro-channel heat sink as claimed in claim 1; Wherein, The cavitation generator in the flat board of microchannel and the cross section of main flow microchannel are square, circular, triangle, trapezoidal or polygon, and the equivalent diameter ratio of cavitation generator and main flow microchannel is 0.2～0.7.

6. like claim 1 or 5 described micro-channel heat sinks, wherein, the cavitation generator in the flat board of microchannel is to be located at equally spacedly on the main flow microchannel.

7. like claim 1,4 or 5 described micro-channel heat sinks, wherein, the number of main flow microchannel is confirmed according to the heating area of heater element.

8. device of measuring the said micro-channel heat sink performance of claim 1 comprises:

The fluid intake of micro-channel heat sink connects a reservoir through a kinetic pump, and the fluid issuing of micro-channel heat sink is connected to cooler through a flowmeter, and this cooler connects reservoir, makes the liquid in the reservoir form circulation;

The fluid intake of micro-channel heat sink respectively is connected a thermocouple respectively with fluid issuing, measures the fluid temperature of micro-channel heat sink fluid intake and fluid issuing respectively;

The dull and stereotyped heater element in microchannel connects a thermocouple, measures the heating wall temperature;

The inlet pressure measurement port of micro-channel heat sink and outlet pressure measurement port respectively are connected with pressure sensor respectively, measure the inlet pressure and the outlet pressure of micro-channel heat sink.

9. device as claimed in claim 8; Wherein, between the fluid intake and reservoir of micro-channel heat sink, and valve is installed respectively between the fluid issuing of micro-channel heat sink and the flowmeter; With the fluid intake of adjusting micro-channel heat sink and the pressure of fluid issuing, reach the condition of liquid cavitation.

10. device as claimed in claim 8, wherein, flowmeter, thermocouple and pressure sensor all are connected to data collecting system, and handle and analyze through computer.

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