铜粉粒径对烧结式热管传热性能的影响

为了进一步优化烧结式吸液芯的结构,提高热管的热传导性能与效率,研究了外径分别为5、6、8mm和吸液芯厚度为0.5～0.6 mm的热管的传热特性,结果发现:铜粉粒径分布比较集中时,如果其平均粒径增大,吸液芯的孔隙率和热管的极限传输功率(MHTP)均会增大,热管的冷凝端温差及总热阻则略微减小;不同粒径范围的铜粉混合时,热管的冷凝端温差及总热阻在不同外径的热管内的变化规律不同;含70%小粒径铜粉的烧结式热管的MHTP最小,且粒径越小MHTP越低;含70%大粒径铜粉的烧结式热管的MHTP仅次于全部为大粒径铜粉的烧结式热管的MHTP;铜粉粒径的范围越小,热管的性能越优,平均粒径为(165±15)μm的铜粉适合于制作薄壁烧结式热管.

Effect of Copper Particle Size on Heat Transfer Performance of Sintered Heat Pipe

In order to optimize the structure of sintered powder wick and improve the thermal conductivity and efficiency of heat pipes,the heat transfer characteristics of the sintered heat pipes with the outer diameters of 5,6 and 8 mm and with a wick thickness ranging from 0.5 to 0.6 mm are discussed.The results show that,when the copper particle size distribution is concentrated,both the porosity of the wick and the maximum heat transfer power(MHTP) of the heat pipe increase with the average particle size,while the temperature difference at the condensation end and the total thermal resistance both slightly decreases,and that,when the particles in different sizes are mixed,the variation rules of the temperature difference at the condensation end and the total thermal resistance are different for heat pipes with different outer diameters.Moreover,it is found that the MHTP of the heat pipe decreases with the copper particle size and reaches the minimum when the pipe is sintered with 70% of small-size particles,that the MHTP of the heat pipe sintered with 70% of large-size particles is only second to that of the pipe sintered entirely with large-size particles,that a more concentrated particle size favors the performance of the heat pipe,and that copper powders with an average particle size of(165±15)μm is appropriate to the manufacturing of heat pipes.