颗粒形貌及表面润湿性对毛细芯及环路热管性能的影响

Effect of Particle Morphology and Surface Wettability on Performance of Porous Wick and Loop Heat Pipe

利用粒径63.5μm的球形铜粉和66.0μm的枝状铜粉烧结了两种不同结构的环路热管(Loop heat pipe,LHP)毛细芯,并采用H2O2化学氧化方法对毛细芯进行了润湿性改进处理,试验分析了颗粒形貌和润湿性对毛细芯的吸液性能以及LHP换热性能的影响规律。结果表明,与球形颗粒毛细芯相比,工质在枝状颗粒毛细芯内具有较快的爬升速率。对于改性前的亲水毛细芯,蒸馏水在枝状颗粒毛细芯内爬升18.0cm所用时间降低了约85.0s,且枝状颗粒毛细芯的总吸液质量较大,为球形颗粒毛细芯吸液量的2.0倍。毛细芯经H2O2氧化后表层生长出纳米级的片状结构,增强了毛细芯的亲水性,吸液性能得以提高。热性能试验结果显示,与球形颗粒毛细芯LHP相比,枝状颗粒毛细芯LHP的运行温度较低。在加热功率为280W时,运行温度降低了7.6℃。

Two kinds of loop heat pipe(LHP)porous wick with different structures are sintered by spherical copper powder and the branch copper powder witch particle size is 63.5μm and 66.0μm.The wettability of the porous wick is improved by chemical oxidation with H2 O2.The effects of particle morphology and wettability on the porous wick liquid absorption and LHP heat transfer performance are analyzed.The results show that the working fluid has a fast climbing rate in the porous wick of branch particles.When the porous wick is hydrophilic,the suction time for distilled water climbing to 18.0 cm in the branch porous wick is about 85.0 s less than that of the spherical porous wick,and the total liquid absorption mass is larger,which is 2.0 times larger than that of the spherical porous wick.The surface layer of the porous wick has nano-scale structure oxidized by H2 O2,which enhances the hydrophilicity of the porous wick and improves the liquid absorption performance.Compared with spherical particle capillary LHP,branch particle capillary LHP operates at a lower temperature.When the heating power is 280 W,the operating temperature decreases by 7.6℃.