Test device and test method for limit heat-flow density of porous material for heat pipe

Abstract

The invention relates to a test device and a test method for limit heat-flow density of a porous material for a heat pipe. The test device comprises a heat insulation material, a stainless steel barrel, a test block, a condensation pipe, a heat transfer block, a heater and thermocouples. The method comprises the following steps of: increasing the power of the heater so as to gradually increase the heat quantity of the porous material and intensify the boiling of the porous material till the occurrence of a heat transfer limit, and calculating the limit heat-flow density of the material through data recorded by each thermocouple. The device and the method have the advantages that: the heat resistance and the heat transfer capability of different capillary structures during boiling can be compared by the device and the method, the test results are stable and reliable, and the device and the method can provide help for the design of the capillary structures of heat pipes.

Description

Technical field [0001] The invention belongs to the technical field of heat transfer of heat pipes, and specifically relates to a testing device and a testing method for the limit heat flux density of a porous material for a heat pipe. Background technique [0002] With the development of electronic products in the direction of miniaturization, light weight and multi-function, the heat dissipation problem of electronic products has become more and more prominent. Traditional heat dissipation methods include metal heat sinks and air convection, but these methods have gradually been unable to meet the heat dissipation requirements of electronic products, and there is an urgent need for a stronger heat dissipation method. [0003] When the heat pipe is working, the working fluid in the pipe undergoes a phase change, and the latent heat of the phase change is transferred through the heat pipe. Generally, the thermal conductivity of a heat pipe is 100 to 10,000 times that of pure coppe...

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Problems solved by technology

However, the simple channel structure also has some disadvantages: due to the large capillary radius, the capillary pressure it generates is small; when the heat pipe is partially overheated and partially burnt out, the viscosity limit will suddenly appear, causing the temperature of the heat pipe to rise rapidly and the heat pipe to burn out;

[0008] However, due to the too small permeability, the working fluid will produce a large pressure loss when passing through the sintered capillary core;

[0009] 3. The capillary pressure of the wire mesh capillary core is in the middle, and the permeability is small, so the working fluid will have a large pressure loss, and its thermal resistance is also large, and the lower heat will reach the heat transfer limit

In addition to the three basic structures of the capillary core structure, there is also a composite capillary core structure composed of the above three basic structures (such as a combination of a channel structure and a sintered structure). Different structures have different heat transfer capabilities. The pores of the same structure The difference in heat transfer rate and pore size will also cause a great change in heat transfer capacity. On the other hand, the boiling heat transfer process of porous materials is very complicated, and it is still impossible to use theory to explain the boiling process of porous materials.

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