R123在套管式蒸发器中的换热特性

Evaporating Heat Transfer Characteristics of R123 in a Double–pipe Evaporator

该文对饱和压力分别为0.152MPa和0.2MPa的R123在水平套管蒸发器中的换热特性进行了实验研究。探讨了工质质量流速、热流密度、蒸发压力以及工质干度对管内流动沸腾换热系数的影响规律。同时,分别采用Shah关联式、Gungor-Winterton关联式以及Kandlikar关联式对相同实验工况下R123的管内流动沸腾换热系数进行了计算,并与实验结果进行了对比。结果表明:当蒸发压力和热流密度一定时,管内流动沸腾换热系数随工质质量流速的增大而增大;当蒸发压力和质量流速一定时,随热流密度的增大而增大;当热流密度和质量流速一定时,随蒸发压力的升高而增大,而随工质干度的增大先增大后减小。相较于Shah关联式和Gungor-Winterton关联式,采用Kandlikar关联式计算精度更高。

In this paper,flow boiling heat transfer characteristics of R123 inside a double-pipe evaporator at two different saturation pressure,0.152MPa and 0.2MPa,are experimentally investigated with various mass flow rates of working fluid,different heat fluxes and various vapor qualities.Under the same experimental condition,flow boiling heat transfer coefficients are calculated using Shah’s correlation,Gungor-Winterton’s correlation and Kandlikar’s correlation.The investigation results show that flow boiling heat transfer coefficient increases as the working fluid mass flow rate increases,when the saturation pressure and heat fluxes are constant.It also increases as the heat flux increases,when the saturation pressure and mass flow rate are constant.And it increases as the saturation pressure increases,when the heat fluxes and mass flow rate are constant.However,it increases first and then decreases as the vapor quality increases.Comparing the heat transfer coefficient of experimental results with that correlation values using Shah’s correlation,Gungor-Winterton’s correlation and Kandlikar’s correlation,it can be seen that the experimental results have a good agreement with Kandlikar’s correlation.