水-甲醇混合工质振荡热管温度振荡及传热特性研究

通过实验研究了水-甲醇混合工质振荡热管充液率分别为55%、62%、70%、90%下,体积比分别为13∶1、4∶1、1∶1、1∶4、1∶13时的温度振荡以及热阻特性,并与水、甲醇纯工质振荡热管进行了对比。研究表明,混合工质振荡热管的振幅较纯工质大且较为均匀;较大充液率时(62%及以上),大多数混合工质振荡热管热阻大于两种纯工质;中等充液率时,部分振荡热管出现烧干现象,受黏度影响,大多数混合工质振荡热管出现烧干现象时的功率较小,热阻较纯工质大。但是,在水中加入少量甲醇(13:1)做工质的振荡热管在充液率为55%下不易发生烧干,且热阻较其他工质低。振荡热管的热阻特性受工质黏度、气液相平衡等因素的共同作用,在不同工况下,各因素作用效果不同。

Experimental Investigation on Thermal Performance of Oscillating Heat Pipe with Water/Methanol Mixture as Working Fluids

An experimental investigation was performed on the oscillating characteristics and thermal resistances of the oscillating heat pipe(OHP) with water/methanol mixture under varied mixing ratios(i.e. 13:1,4:1,1:1,1:4 and 1:13) and filling ratios (i.e. 90%,70%,62% and 55%) , which is compared with the pure working medium, water and methanol. Experimental results showed that the amplitude of the OHP with mixture was larger than the pure working fluid. Generally, the thermal resistance of the OHP with the mixture working medium was mostly higher than that with pure one when the filling ratio was more than 62%.The OHP with mixture was easier to dry out than that with pure one. When the filling ratios were 55%, the thermal resistance of the OHP with mixture rises faster. Specially, the working medium with little methanol (13:1) and much water was ideal because of the high heating power when dry out in 55% filling ratio. The thermal resistance of the OHP was mainly determined by the viscosity of working medium, phase equilibrium and so on. The primary factor changes in different working conditions.