工质R245fa水平管内流动沸腾换热的试验研究

The Experimental Study on Flow Boiling Heat Transfer of Working Fluid R245fa in Horizontal Tube

设计了管内沸腾换热系数及总传热系数测定试验台架,对R245fa工质在内径6 mm水平光管内的流动沸腾换热特性进行试验研究。测试质流密度为50~150 kg/(m^2·s),工质蒸发温度为50,60和70℃。结果表明:随着工质含汽率的增加,R245fa的流动沸腾换热系数呈先增大后降低趋势。对于304不锈钢套管式换热器,烟气与R245fa工质进行换热的总传热系数约在40~65 W/(m^2·K)。

A bench - scale facility was designed for testing the flow boiling heat transfer coefficient and the total heat transfer coefficient. The boiling heat transfer characteristics of the R245fa refrigerant were studied in a horizontal smooth tube with 6 mm inner diameter. The parameters investigated were mass flow rate （50 -150 kg/（m^2· s））,evaporation temperature （50,60 and 70℃）. The results showed that the flow boiling heat transfer coefficient of R245fa increased with the increase of rate of vaporcontent, and decreased slightly with the further increase of rate of vapor content. The total heat transfer coefficient of the flue gas and the R245fa is about 40 -65 for the 304 stainless steel heat exchanger.