R245fa在丁胞型扁管内流动沸腾传热和压降特性的实验研究  

Experimental Study on Flow Boiling Heat Transfer and Pressure Drop Characteristics of R245fa in a Dimpled Flat Tube

作　　者：封叶 丁普贤 邵双全 Feng Ye;Ding Puxian;Shao Shuangquan(College of Modern Logistics,Guangzhou Panyu Polytechnic,Guangzhou,511483,China;School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan,430074,China)

机构地区：[1]广州番禺职业技术学院现代物流学院,广州511483 [2]华中科技大学能源与动力工程学院,武汉430074

出　　处：《制冷学报》2024年第5期145-151,共7页Journal of Refrigeration

基　　金：国家自然科学基金(52076085)资助项目。

摘　　要：实验研究了丁胞型扁管内R245fa的流动沸腾传热和压降特性,重点分析了干度和热流密度的影响。实验结果表明:随着干度的增大,表面传热系数呈先增大后减小的趋势,并且表面传热系数最大位置处对应的干度受热流密度的影响。当热流密度为2、5、10 kW/m2时,表面传热系数分别在干度为0.35、0.40、0.45时达到最大值,随后逐渐降低。增大热流密度对摩擦压降的影响很小,但有利于提升表面传热系数。分析表明,表面传热系数随着干度的增大而降低是由于核态沸腾受到抑制所致。对比R245fa和R134a的实验结果发现,干度和热流密度对表面传热系数的影响不同。此外,在相同工况下,R245fa和R134a的表面传热系数比值在0.64~1.31之间。In this study,the flow boiling heat transfer and pressure drop of R245fa in a dimpled flat tube were experimentally measured.The effects of vapor quality and heat flux were analyzed accordingly.The experimental results showed that with an increase in vapor quality,the surface coefficient of heat transfer first increased and then decreased,and the corresponding vapor quality at the maximum surface coefficient of heat transfer was affected by the heat flux.When the heat fluxes were 2 kW/m 2,5 kW/m 2,and 10 kW/m 2,the surface coefficient of heat transfer reached its maximum value at vapor qualities of 0.35,0.40,and 0.45,respectively,and then gradually decreased.Increasing the heat flux had little effect on the frictional pressure gradient,but it was beneficial for improving the surface coefficient of heat transfer.The decrease in the surface coefficient of heat transfer with an increase in vapor quality was due to the suppression of nucleate boiling.A comparison of the experimental results for R245fa and R134a indicated that vapor quality and heat flux have different effects on the surface coefficient of heat transfer.Under the same conditions,the ratio of the surface coefficient of heat transfer between R245fa and R134a ranged from 0.64 to 1.31.

关 键 词：流动沸腾 表面传热系数 丁胞型扁管 制冷剂 

分 类 号：TB611[一般工业技术—制冷工程] TB657.5