R404A小管径冷凝换热与压降关联式的适配性  

Suitability of R404A Condensation Heat Transfer and Pressure Drop Correlations for Small Diameter Tube

作　　者：王学东[1] 柳建华[1] 宋吉[2] 高屹峰[2] 朱立珺 

机构地区：[1]上海理工大学能源与动力工程学院,上海200093 [2]国际铜业协会(中国),上海200020

出　　处：《制冷学报》2017年第2期22-28,共7页Journal of Refrigeration

基　　金：上海市教育委员会重点学科资助项目(J50502)资助~~

摘　　要：针对R404A的冷凝换热与压降关联式有很多,但均为基于7 mm或者9.52 mm等大管径光管或者强化管,针对5 mm管径的关联式也都是适用于其它制冷剂,没有R404A小管径冷凝直接适用的关联式。本文采用实验测试与理论计算结合论证的方法,利用控制变量法、性质相似制冷剂优先法筛选出一批关联式,大量对比由关联式计算与由实验数据计算得出的换热系数与压降的偏差,研究关联式的适用性及可修正性。结果表明:M.K.Dobson等提出的冷凝换热关联式乘以修正系数2.13,能很好预测R404A在内螺纹管中的冷凝换热系数,与实验值正偏差为+15.51%,负偏差为-14.13%。X.C.Huang等提出的摩擦压降关联式能很好预测R404A在小管径内螺纹管内冷凝的摩擦压降,与实验值的正偏差为+12.56%,负偏差为-13.58%,两者均可为换热器设计计算提供较准确的理论指导。Many correlations have been proposed about R404A condensation heat transfer and pressure drop, but all of them apply for smooth tubes or microfin tubes with big diameter. Some correlations are based on 5 mm diameter tube, but the refrigerant is not R404A. Up to now, there is no correlation for R404A condensation heat transfer and pressure drop with 5 mm diameter tube. In this paper, a num- ber of correlations were selected by variable-controlling and giving priority to refrigerant with similar properties, combining experimental test and theoretical calculation, deviation between the calculated and experimentally measured values have been compared through a large amount of data to demonstrate the applicability and revisability of the correlations. The research results indicate that modified condensation heat transfer correlation proposed by M. K. Dobson et al（ multiplied by the correction factor 2.13 ） shows good predictability of condensa- tion heat transfer coefficient of R404A in small diameter microfin tube within a deviation of -14.13% to ＋ 15.51%. The friction pres- sure drop correlation proposed by X.C. Huang et al can well predict the friction pressure drop of R404A in small diameter microfin tube within a deviation of - 13.58% to ＋ 12.56%. Both correlations can provide more accurate theoretical guidance for the calculation and design of heat exchanger.

关 键 词：关联式 小管径 冷凝 换热系数 压降 R404A 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TB611[动力工程及工程热物理—热能工程]