AN EXPERIMENTAL COMPARISON OF EVAPORATION AND CONDENSATION HEAT-TRANSFER COEFFICIENTS FOR HFC-134A AND CFC-12

被引：51

作者：

ECKELS, SJ

PATE, MB

机构：

[1] Department of Mechanical Engineering, Iowa State University, Ames

来源：

INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID | 1991年 / 14卷 / 02期

关键词：

EXPERIMENTAL HEAT TRANSFER COEFFICIENTS; ALTERNATIVE REFRIGERANTS; HFC-134A; CFC-12;

D O I：

10.1016/0140-7007(91)90078-U

中图分类号：

O414.1 [热力学];

学科分类号：

摘要：

Experimental heat transfer coefficients are reported for HFC-134a and CFC-12 during in-tube single-phase flow, evaporation and condensation. These heat transfer coefficients were measured in a horizontal, smooth tube with an inner diameter of 8.0 mm and a length of 3.67 m. The refrigerant in the test-tube was heated or cooled by using water flowing through an annulus surrounding the tube. Evaporation tests were performed for a refrigerant temperature range of 5-15-degrees-C with inlet and exit qualities of 10 and 90%, respectively. For condensation tests, the refrigerant temperature ranged from 30 to 50-degrees-C, with inlet and exit qualities of 90 and 10%, respectively. The mass flux was varied from 125 to 400 kg m-2 S-1 for all tests. For similar mass fluxes, the evaporation and condensation heat transfer coefficients for HFC-134a were significantly higher than those of CFC-12. Specifically, HFC-13a showed a 35-45% increase over CFC-12 for evaporation and a 25-35% increase over CFC-12 for condensation.

引用

页码：70 / 77

页数：8

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