水平微肋管内有机工质R245fa的沸腾换热性能  

Flow boiling heat transfer characteristics of R245fa in horizontal micro-fin tube

作　　者：王志奇[1] 刘力文[1] 贺妮 夏小霞[1,2] 彭德其[1] 张建平[1] 明镇洋 WANG Zhiqi;LIU Liwen;HE Ni;XIA Xiaoxia;PENG Deqi;ZHANG Jianping;MING Zhenyang(Institute of Mechanical Engineering,Xiangtan University,Xiangtan 411005,China;School of Energy Science and Engineering,Central South University,Changsha 410083,China)

机构地区：[1]湘潭大学机械工程学院,湖南湘潭411005 [2]中南大学能源科学与工程学院,湖南长沙410083

出　　处：《中南大学学报（自然科学版）》2018年第3期741-746,共6页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(51405415);湘潭大学博士基金资助项目(13QDZ04)~~

摘　　要：为增强有机朗肯循环发电系统中蒸发器的传热能力,对水平微肋管内新型有机工质R245fa的沸腾换热性能进行实验研究。研究结果表明:R245fa沸腾换热系数随质量流速增大而提高,随饱和温度和热流密度增大而减小;随着干度增大,沸腾换热系数先增大后降低,存在1个临界干度;在实验条件下,临界干度约为0.4,并与实验工况有关;超过临界干度时,质量流速对R245fa沸腾换热系数的强化作用增大,而饱和温度对沸腾换热的抑制作用增大;在4种常用关联式中,KANDLIKAR关联式对R245fa沸腾换热性能的预测较精确,预测值与91.6%的实验值偏差在±25%以内,绝对平均偏差为11.2%,能满足工程设计要求。To intensify the heat transfer process of evaporator in organic Rankin cycle(ORC),flow boiling heat transfer characteristics of R245fa in a horizontal micro-fin tube were tested.The results show that boiling heat transfer coefficient increases with the increase of mass velocity of R245fa,while it decreases with the increase of saturation temperature and heat flux density.With the increase of vapor quality,boiling heat transfer coefficient reaches the maximum at a critical vapor quality.The critical vapor quality is about 0.4,and it is varied according to the operating conditions.When vapor quality is larger than the critical value,heat transfer coefficient can be promoted more remarkably at higher mass velocity or lower saturation temperature.Among the four widely used correlations,KANDLIKAR correlation has high forecast accuracy,the deviation between the forecast value and 91.6%of experimental values is within±25%,and the absolute mean deviation is 11.2%.The correlation is more precise to predict boiling heat transfer coefficients,and it can be used for the design of evaporator in ORC.

关 键 词：微肋管 R245FA 沸腾换热 预测关联式 

分 类 号：TK124[动力工程及工程热物理—工程热物理]