微圆管内非共沸混合工质流动沸腾传热强化  

Flow boiling heat transfer enhancement of refrigerant mixtures in micro-tubes

作　　者：胡自成[1] 马虎根[2] 王谦[1] 

机构地区：[1]江苏大学能源与动力工程学院,江苏镇江212013 [2]上海理工大学动力工程学院,上海200093

出　　处：《江苏大学学报（自然科学版）》2009年第2期160-164,共5页Journal of Jiangsu University：Natural Science Edition

基　　金：上海市高等学校科学技术发展基金资助项目(01F09);江苏大学高级人才专项资助项目(07JDG051)

摘　　要：分别进行了R32/R134a在水平微圆管、细圆管和小尺寸常规管道内的流动沸腾传热试验.在定义微圆管传热强化系数Ec（相对于细圆管和小尺寸常规管道的传热强化系数分别用Ecm和Ecs表示）的基础上,从不同强化管内流动沸腾传热机理的角度分析了Ecm和Ecs在不同试验工况下的变化规律及其与传热机理的关系.结果表明,试验工况范围内Ecm和Ecs分别在1.01~2.33和1.03~3.54之间变化.绝大部分试验工况下Ecm的值较小且变化很小,Ecs则较大且有明显变化;高热通量和高质量干度下Ecm和Ecs的值都较大.微圆管内流动沸腾传热强化效果与传热机理及其转变区域密切相关,当微圆管内传热开始出现恶化和较高热通量下微圆管内核态沸腾传热占绝对主导地位时,微圆管传热强化效果明显.Experimental study was carried out to investigate forced flow boiling enhanced heat transfer in horizontal micro-tube（d=0.86 mm）,mini-tube（d=1.92 mm） and small-tube（d=3.60 mm） of 200 mm heated length with non-azeotropic refrigerant mixtures of R32 and R134a（25%/75%,mass ratio）,respectively.By comparing flow boiling heat transfer coefficient with mini-tube and small-tube,the heat transfer enhancement coefficient（Ec） in micro-tube was defined,so were the Ecm and Ecs for mini-tube and small-tube.The variations of Ecm and Ecs under different working conditions were analyzed according to flow boiling heat transfer mechanisms in different enhanced tube.The results show that Ecm and Ecs vary from 1.01 to 2.33 and from 1.03 to 3.54 respectively.In most working conditions both the value of Ecm and its variation are small,while the Ecs is the opposite.At high heat flux and high mass quality level the values of Ecm and Ecs are large.The flow boiling heat transfer enhancement effect of micro-tube is influenced strongly by heat transfer mechanisms and its transition region in different enhanced tube.Ecm and Ecs are much higher when nucleation boiling mechanisms dominate at high heat flux level and when deterioration of heat transfer begins at high mass quality level in micro-tube.

关 键 词：传热强化 微圆管 流动沸腾 非共沸混合工质 

分 类 号：TK124[动力工程及工程热物理—工程热物理]