R744系统管翅式蒸发器换热性能的优化

The Optimization of Tube-Fin Evaporator Used in R744 System

基于稳态分布参数法,建立了R744系统管翅式蒸发器模拟程序,计算分析了管内制冷剂侧换热系数和压降梯度沿管长的变化特点;通过对管翅式蒸发器结构参数进行敏感性计算分析,得出了传热系数、换热量、制冷剂侧压降以及冷重比等参数与蒸发器主要结构参数之间的变化关系.优化后的管翅式蒸发器在换热量基本相同的情况下,空间体积缩小了24.86%,传热系数提高了5.17%,单位面积换热量提高了15.58%.

Numerical simulation program of tube-fin evaporator in the R744system was established based on the steady-state distribution parameters methods,and the changes of heat transfer coefficient and the gradient of pressure drop on refrigerant side along the tube length were computational analyzed.With the sensitivity analysis of structure size parameter of tube-fin evaporator,the variable relationship has been gotten among heat transfer coefficient,heating capacity,pressure drop on refrigerant side,cooling-weight ratio and the main structure size of the evaporator,and optimized the tube-fin evaporator.After optimization of the tube-fin evaporator,the space volume of the evaporator is reduced 24.86%,heat transfer coefficient is increased 5.17%,heat transfer of per unit area is increased by 15.58%,correspondly in the same case which the heat transfer is essentially constant.