单流程蒸发器表面温度场均匀性的影响因素研究

Research of the Influence Factors on Surface Temperature Field Uniformity of Single Flow Evaporator

改善蒸发器表面温度场的均匀性对提高其换热效率具有决定性作用。设计出一种类似平行流蒸发器的圆管单流程蒸发器,改变其集液管和蒸发管衔接处的孔径大小以及制冷剂入口流速,并进行了蒸发器管路的水力计算和相应的实验研究,得出管路中间截面的温度分布。模拟结果表明:在结构一定的条件下,集液管内的制冷剂来流速度具有决定性作用。当集液管内的来流速度在0.04m/s时,蒸发器各支管的温度分布最为均匀;同时在制冷剂流量一定时,支管数及各蒸发管与集液管衔接处的孔径大小也影响着温度分布。试验结果证明了此结论:在一定的液态制冷剂集管入口流速下,最小孔径为0.4mm时,具有8根支管的单流程蒸发器比10根支管的单流程蒸发器具有均匀的温度场。研究结果为研发高效率的平行流蒸发器提供了一定的理论和试验基础。

For evaporator,improving its surface temperature field uniformity plays a key role in its heat transfer efficiency. We designed a circular tube single flow evaporator similar to the parallel flow evaporator. The temperature distribution of the middle section of the evaporator was obtained by the hydraulic calculation of evaporator and the corresponding experiment under different working conditions including different diameter of the pore connecting the collection tube and the evaporator tube and different in- let velocity of the refrigerant in the collection tube. The simulation results show that the inlet velocity of collection tube counts much for a fixed structure evaporator. When the inlet velocity is 0.04m/s, the temperature distribution is more uniform. If the re- frigerant flow is fixed, the pore size affects the temperature distribution. The experimental results show that in a certain inlet velocity ,the temperature field of the evaporator with 8 tubes is more uniform than that of the evaporator with 10 tubes when the smallest pore size is 0.4mm. The results provide theoretical and experimental basis for the development of high efficient parallel flow evaporator.