Experiment on Boiling Heat Transfer of Refrigerant R134a in Mini-channels  

作　　者：ZHAN Hongbo SHEN Hao WEN Tao ZHANG Dalin 

机构地区：[1]College of Aerospace Engineering,Nanjing University of Aeronautics and Astronautics [2]Shanghai Aircraft Airworthiness Certification Center of CAAC

出　　处：《Transactions of Nanjing University of Aeronautics and Astronautics》2019年第1期80-87,共8页南京航空航天大学学报（英文版）

摘　　要：The flow boiling heat transfer characteristics of refrigerant R134 a flowing inside two different kinds of minichannels are investigated. One channel is multi-port extruded with the hydraulic diameter of 0.63 mm,and the other one is rectangular with offset fins and a hydraulic diameter of 1.28 mm. The experiments are performed with a mass flow rate between 68 and 630 kg/(m^2·s),a heat flux between 9 and 64 kW/m^2,and a saturation pressure between 0.24 and 0.63 MPa,under the constant heat flux heating mode. It is found that the effect of mass flow rate on boiling heat transfer is related to heat flux,and that with the increase of heat flux,the effect can only be efficient in higher vapor quality region. The effects of heat flux and saturation pressure on boiling heat transfer are related to a threshold vapor quality,and the value will gradually decrease with the increase of heat flux or saturation pressure. Based on these analyses,a new correlation is proposed to predict the boiling heat transfer coefficient of refrigerant R134 a in the mini-channels under the experimental conditions.The flow boiling heat transfer characteristics of refrigerant R134 a flowing inside two different kinds of minichannels are investigated. One channel is multi-port extruded with the hydraulic diameter of 0.63 mm,and the other one is rectangular with offset fins and a hydraulic diameter of 1.28 mm. The experiments are performed with a mass flow rate between 68 and 630 kg/(m^2·s),a heat flux between 9 and 64 kW/m^2,and a saturation pressure between 0.24 and 0.63 MPa,under the constant heat flux heating mode. It is found that the effect of mass flow rate on boiling heat transfer is related to heat flux,and that with the increase of heat flux,the effect can only be efficient in higher vapor quality region. The effects of heat flux and saturation pressure on boiling heat transfer are related to a threshold vapor quality,and the value will gradually decrease with the increase of heat flux or saturation pressure. Based on these analyses,a new correlation is proposed to predict the boiling heat transfer coefficient of refrigerant R134 a in the mini-channels under the experimental conditions.

关 键 词：FLOW BOILING heat transfer two-phase FLOW REFRIGERANT R134A channels with offset FINS multi-portchannel 

分 类 号：TK124[动力工程及工程热物理—工程热物理]