开式系统中水膜闪蒸换热特性的实验研究

针对开式系统中水膜闪蒸的换热特性进行了实验研究.实验参数选择如下:循环水过热度为1~15 K;闪蒸室压力分别为20.4、30.2、47.4 kPa;水膜厚度分别为100和300 mm;循环水流量分别为0.028、0.056、0.083 kg/s.实验结果表明:闪蒸换热系数的变化范围为60~140 kW/(m2.K),并随过热度的增大而减小,随闪蒸室内饱和压力的升高而增大,随水膜厚度的增大而减小.根据实验结果,基于闪蒸过程类似核态沸腾,给出了换热系数与各影响参数之间关系的实验关联式,与实验结果的误差小于27%.

Experimental Study on Heat Transfer Characteristics of Flash Evaporation of Water Film in Open System

Heat transfer characteristics of flash evaporation of water film in an open system were studied.The tests were conducted at superheat temperature differences of 1-15K,flash evaporation pressures of 20.4, 30.2 and 47.4 kPa,water film thicknesses of 100 and 300 mm,and mass flux of 0.028,0.056,0.083 kg/s.The results show that under the operating condition,heat transfer coefficient ranges from 60 to 140 kW/(m~2 K) which decreases with the increase of superheat,increases with the increase of flash evaporation pressure and decreases with the increase of water film thickness.According to the results in this experiment,based on the similarity between flash evaporation and nuclear boiling,an experimental expression of heat transfer coefficient with all of the influence parameters was presented with the maximum error of 27%.