微尺度水平管内沸腾换热特性研究

对不同质量分数下非共沸混合工质(R134a/R32)在微尺度管道内的流动沸腾换热特性进行了比较和分析,阐述了热流密度、质量流量和质量干度对换热的影响。结果表明:热流密度对换热的影响随着质量流量的增加而愈加明显;在质量分数为75%/25%和65%/35%时,换热系数随着质量流量的增大而增大;而质量分数为85%/15%时,换热系数随质量流量的变化先增加后减小;随着质量干度的增加,换热系数在各质量分数下基本上都呈上升趋势。

Study on Flow Boiling Heat Transfer in Horizontal Microtube

The characteristics of flow boiling heat transfer in horizontal microtube were investigated for non-azeotropic mixture(R134a/R32) under different mass fractions.The influences of heat flux, mass flow rate,quality on the heat transfer were analyzed.The results show that heat flux has a significant effect on heat transfer as the mass flow rate grows.When the mass fractions are 75%/25% and 65%/35%,heat transfer coefficient grows with the increase of mass flow rate,while the mass fraction is 85%/15%,heat transfer coefficient increases first and then decreases.As the quality grows, heat transfer coefficient mainly keeps a increase trend in each condition.