再循环重力供液蒸发器管内换热性能预测

Performance prediction of heat exchange inside the tube of evaporator with liquid refrigerant supplied by gravity using recycle refrigerant

为了找出适用于再循环重力供液蒸发器管内强制对流沸腾换热系数的关系式,通过对以R404A为制冷剂的重力供液实验台的研究,编程计算出J.Chawla关系式及Shah关联式对重力供液沸腾换热系数进行预测值。与实验结果比较可知:J.Chawla关系式在较低温度下较接近于实验值,Shah关联式在较高的温度下可以对实验值进行预测,两种关系式相结合的方法就可以较好对重力供液蒸发器管内沸腾换热进行预测。

In order to find the equation fitting for forced-convection boiling heat transfer inside the pipes of evaporator with liquid refrigerant supplied by gravity using recycle refrigerant,by experiment research to a test-bed of liquid refrigerant of R404A supply by gravity,this study adopted the combine of J.Chawla and Shah relation to predict the coefficient of heat transfer.Compared with the results of experiment,it could be found that J.Chawla relation would fit better at lower vaporization temperature,meanwhile Shah relation fit better at higher vaporization temperature.So the way to combine the two relations was used to predict the heat exchange inside the tube of evaporator with liquid refrigerant supply by gravity using recycle refrigerant.