Porous silicon nitride capillary core for a loop heat pipe

Abstract

A porous silicon nitride capillary core for a loop heat pipe is formed by firing raw materials including silicon nitride powder, a sintering aid and a pore forming agent, wherein the content of silicon nitride is not smaller than 90% by weight. The average grain size of the silicon nitride powder ranges from 0.1 micrometer to 10 micrometers, and the proportion of the alpha-phase silicon nitride is larger than 90%. Micropores included in the porous silicon nitride capillary core communicate with one another, the pore diameter of the micropores ranges from 0.5 micrometer to 5 micrometers, and the open porosity is larger than 50%. The porous silicon nitride capillary core is formed by sintering the silicon nitride powder, has good chemical stability and is resistant to corrosion of acid and alkali, decomposition of working media in the loop heat pipe can be effectively restrained, and the service life of the loop heat pipe is prolonged. Meanwhile, the porous silicon nitride capillary core is high in brittleness and good in machining performance, the surface micropores cannot be closed during outer wall finish machining, and the high open porosity of the capillary core is guaranteed.

Description

technical field [0001] The invention belongs to the field of heat control, and relates to a loop heat pipe, in particular to a capillary core component used on the loop heat pipe. Background technique [0002] With the continuous development of space remote sensing technology, traditional channel heat pipes are gradually difficult to meet the heat dissipation or temperature control requirements such as the large number of heat sources in the remote sensor, small size, high power, high temperature control accuracy, and flexible links in the heat transfer path. The loop heat pipe is a two-phase fluid loop system that uses capillary force to drive the circulation of the working fluid and complete the heat transfer. It has the advantages of low thermal resistance, large heat transfer, long heat transfer distance, high temperature control accuracy, flexible heat conduction, and flexible installation. , can effectively solve the above problems. [0003] The evaporator is the core...

AI Technical Summary

Problems solved by technology

However, due to the high plasticity of metal materials, the existing processing methods such as turning, grinding, and electric sparks easily lead to the closure of the micropores on the outer surface of the capillary core, which greatly reduces the porosity of the openings, which in turn leads to a decrease in the performance of the loop heat pipe, or even failure.

Metal powder sintered capillary core also has the phenomenon of slag and powder falling, which will cause the loop heat pipe to fail due to partial blockage in severe cases

In addition, the metal powder sintered capillary wick has a high thermal conductivity, and the heat leakage from the evaporator to the liquid receiver is large, which is not conducive to the start-up and stable operation of the loop heat pipe.

Images