Abstract: Microfin tube is one of the most popular enhancements for in-tube boiling and condensation of refrigerants. The reason for its popularity is the larger heat transfer enhancement relative to the slightly increased pressure drop. Because of its outstanding performance, it has strongly attracted the attention of a large number of investigators, and numerous papers have been published on microfin tubes [1～3] .However, almost all microfin tubes studied by those investigators were single helix (2-D) microfin geometry. A new 3-D microfin tube was first developed by Du and Xin, et al . (1995). Their 3-D microfin tube is seamless. Xin and Wang had studied the in-tube condensation heat transfer performance of the 3-D microfin tube with R-11 and steam. In 1996, Chamra and Webb et al . presented another 3-D microfin tube, which were manufactured by using high frequency welding method. They reported the condensation performance with refrigerant R22. The experimental data of the two 3-D microfin tubes in their papers demonstrated higher heat transfer performances as compared with 2-D micro-fin tubes. However, no one reported the refrigerant R134a condensation performance in 3-D microfin tube. The purpose of this paper focuses on the condensation performance for refrigerant R134a in a new 3-D micro -fin tube. The experiments are carried out at different inlet pressure: 0.51-0.77 MPa ( temperature: 18 - 30 ℃), the mass flux is between 125 and 285 kg/m 2·s, and the vapor quality, x , is from 1.00 to 0.14. The data are compared with those of smooth tube, which are calculated with Shahs correlation. The ratio of enhancement for condensation is 1.7-3 (at x =0.6) in the experimental range of the mass flux noted above. The average ratio of enhancement is 2.2. The effects of mass flux and quality are also reported.

摘要： 以R1 34a为工质 ,对一种新型水平三维内微肋管内凝结传热性能进行了实验 .实验管件为外径 1 6mm ,内径 1 2mm的铜管 ,实验工况范围为 :质量通量 1 2 5～ 2 85kg·m- 2 ·s- 1 ;进口压力 0 .51～ 0 .77MPa ;蒸汽干度0 .1 4～ 1 .将实验得到的局部传热系数与相同工况下Shah的水平光滑管内凝结传热关系式的预测值进行了比较 ,结果在本实验质量通量范围内 ,该三维内微肋管的局部凝结传热系数 (x =0 .6时 )是光管的 1 .7～ 3倍 ,平均强化比为 2 .2 .