Abstract

The present study aimed to conduct an experimental examination of heat transfer increase using tubes with extended surface of twisted fins for the condensation of vapor R-406A in horizontal tubes. The experimental setup comprised a main counter flow double-tube condenser, with water as the cooling fluid. Further, test and secondary condensers were used to reach desired vapor qualities. The tests were conducted on a smooth tube and four different tubes with extended surface of twisted fins and collected for different mass flow rate of refrigerant and in each mass flow rate for six different vapor quality. The refrigerant mass flow, temperature of refrigerant inlet water and condenser outlet water, were measured in each test. Also, the heat transfer coefficients were obtained based on the former data for different states. The results show that for the tubes with extended surface of fins, heat transfer enhanced by decreasing the pitch. The use of tubes with extended surface of fins increased the mean heat transfer coefficient by about 47% compared to the smooth tube. Eventually, a new correlation is defined for examination of the condensation heat transfer coefficient of R-406A in circular tubes with extended surface of twisted fins.

摘要

本研究旨在对水平管中蒸汽 R-406A 的冷凝使用具有扭曲翅片延伸表面的管进行热传递增加的实验检查。实验装置包括一个主逆流双管冷凝器，用水作为冷却液。此外，使用测试冷凝器和二级冷凝器来达到所需的蒸汽质量。测试在一根光滑的管子和四根不同的管子上进行，这些管子具有扭曲翅片的延伸表面，并收集了不同质量流量的制冷剂，并在每个质量流量下收集了六种不同的蒸汽质量。在每次测试中测量制冷剂质量流量、制冷剂入口水和冷凝器出口水的温度。此外，传热系数是根据不同状态的先前数据获得的。结果表明，对于具有扩展翅片表面的管子，通过减小螺距增强传热。与光滑管相比，使用具有延伸翅片表面的管使平均传热系数增加了约 47%。最终，定义了一个新的关联式，用于检验 R-406A 在具有扭曲翅片扩展表面的圆管中的冷凝传热系数。