水平微细管内R717两相流换热及流态分析  

Analysis on R717 Two-Phase Flow Heat Transfer and Flow Pattern in Horizontal Micro-Tube

作　　者：张汝行 柳建华[1] 张良[1] ZHANG Ru-hang;LIU Jian-hua;ZHANG Liang(College of Energy and Power Engineering,Iniversity of Shanghai for Science and Technology,Shanghai,China,Post Code:200093)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093

出　　处：《热能动力工程》2020年第12期72-78,共7页Journal of Engineering for Thermal Energy and Power

基　　金：上海市部分院校能力建设专项计划(16060502600)。

摘　　要：搭建了在内径为3 mm的水平光管内氨的两相流换热测试台,分析热流密度、质量流率对两相换热及流态的影响。实验工况:饱和温度-5℃,热流密度15~25 kW/m^(2),质量流率60~150 kg/(m^(2)·s),干度0.1~0.9。结果表明:质量流率对微细管的两相流换热影响较为复杂,质量流率过高抑制核态沸腾,质量流率的增加会强化环状流换热,也会降低干涸的起始干度;热流密度对两相流的换热有两面性,热流密度的增加既会强化管内换热也会加快干涸恶化。通过建立管内的流态预测图,进一步验证了流态的变化趋势。将实测换热系数与现存关联式的预测值进行比较,FANG关联式MAD=19.80%、MRD=-19.30%,具有较好的准确性。A two-phase heat transfer test bench for ammonia in a horizontal smooth tube with an inner diameter of 3 mm was set up.The purpose is to quantitatively and qualitatively analyze the effects of heat flux density and mass flow rate on two-phase heat transfer and flow patterns.The experimental saturation temperature is-5 ℃,heat flux density is 15~25 kW/m^(2),the mass flow rate is 60~150 kg/(m^(2)·s),and the vapor quality is 0.1~0.9.The results show that the effect of mass flow rate on the two-phase flow heat transfer of micro-tubes is more complex.Excessive mass flow rate inhibits nuclear boiling.Increasing the mass flow rate will strengthen the annular flow heat transfer and reduce the initial vapor quality of dryout.Heat flux density has two sides of effects on the heat transfer of two-phase flow.Increasing the heat flux density will not only strengthen the heat transfer in the tube,but also accelerate the drying and deterioration of heat transfer.By establishing the flow pattern prediction map,the change of flow pattern is further verified.Comparing the measured heat transfer coefficient with the predicted value of the FANG correlation,the result shows that the FANG correlation has MAD=19.80% and MRD=-19.30%,which have good accuracy.

关 键 词：微细管 氨 两相流 干涸 

分 类 号：TK124[动力工程及工程热物理—工程热物理]