R245fa在水平强化管外降膜蒸发换热特性的实验研究  

Experimental Investigation on Heat Transfer Characteristics of R245fa Falling Film Evaporation outside Horizontal Enhanced Tube

作　　者：李伟[1] 欧阳新萍[1] 刘冰翛 LI Wei;OUYANG Xinping;LIU Bingxiao(Institute of Refrigeration and Cryogenics, University of Shanghai for Science and Technology, Shanghai 200093, China)

机构地区：[1]上海理工大学制冷技术研究所,上海200093

出　　处：《制冷技术》2017年第4期24-28,61,共6页Chinese Journal of Refrigeration Technology

摘　　要：实验研究了R245fa在水平单管外的降膜蒸发换热特性。实验采用的蒸发管是直径为19mm的双侧强化管,有效长度为2,500mm。本文采用威尔逊法获得管内换热特性,采用热阻分离方法获得管外降膜蒸发换热系数数据;进行了变热流密度(15kW∕m^2~55kW∕m^2)、变蒸发温度(30℃~50℃)和变喷淋流量(0.08kg/(m·s)~0.16kg/(m·s))的实验,获得了管外降膜蒸发换热系数及其变化规律。研究结果表明:随着热流密度的增加,传热系数先增大后减小;随着蒸发温度的升高,传热系数逐渐增大;随着喷淋流量的增加,传热系数先增大后减小。The heat transfer characteristics of R245fa falling film evaporation outside horizontal tube was experimentally investigated.The tested tube was double-side reinforced with an effective length of2,500mm and the diameter of19mm.The Wilson Plot method was used to obtain the inner heat transfer characteristics of reinforced tube and the heat transfer coefficient of falling film evaporation on outside tube was calculated by heat resistance sparating method.The experiments were carried out under the conditions of variable heat fluxes from15kW/m2to55kW/m2,variable evaporation temperatures from30oC to50oC and variable spray flow rates from0.08kg/(m·s)to0.16kg/(m·s).The experimental results showed that,with the increase of heat fluxes,the heat transfer coefficient firstly increased and then decreased;with the increase of the evaporation temperature,the heat transfer coefficient gradually increased;the heat transfer coefficient increased first and then decreased with the increase of the spray flow rate.

关 键 词：强化换热 降膜蒸发 R245FA 

分 类 号：TB64[一般工业技术—制冷工程] TK124[动力工程及工程热物理—工程热物理]