R134a在水平管外降膜蒸发的实验研究  

Experimental Studies on Falling Film Evaporation of R134a Outside Horizontal Tube Bundle

作　　者：赵创要[1] 冀文涛[1] 陶文铨[1] 

机构地区：[1]西安交通大学热流科学与工程教育部重点实验室,能源与动力工程学院,西安710049

出　　处：《工程热物理学报》2015年第1期179-183,共5页Journal of Engineering Thermophysics

基　　金：高等学校博士学科专项科研基金(No.20122102130001);青年科学基金(No.51306140)

摘　　要：实验研究了不同热流密度不同液膜流量下,R134a在垂直布置的七根水平强化管外的降膜蒸发传热特性。结果表明:相同热流密度下在液膜流量较小阶段,管外传热系数随着液膜流量增加而明显增加;随着液膜流量的进一步增大,管1~3的管外传热系数保持不变,管4~7的管外传热系数先增大后减小。同时发现,液膜流量为0.159 kg·m^(-1)·s^(-1)时,随着热流密度的增大所有管的传热性能先增大后减小,并且转折点出现在较小的热流密度下;液膜流量为0.29 kg·m^(-1)·s^(-1)时,管1性能一直增强,管2~4的传热系数随热流密度增大先增大后减小,管5~7的传热系数一直减小,并且管1~4转折点出现在较大热流密度下。The falling film evaporation outside seven horizontal enhanced tubes in a vertical column with various heat flux and film flow rate was experimentally investigated.The results indicated that for the constant heat flux the falling film heat transfer coefficient was greatly increased with increase of film flow rate under smaller film flow rate;with further increase of the film flow rate the falling film heat transfer coefficient tended to be constant for the tubes No.1~3 but firstly increased and then decreased for the tubes No.4~7.It was also found that for the film flow rate of Γ=0.159 kg·m^(-1)·s^(-1),with increase of heat flux the heat transfer of all tubes were firstly enhanced and then deteriorated and the peak values occurred at smaller heat flux;for Γ=0.29 kg·m^(-1)·s^(-1),with increase of heat flux the heat transfer of tube No.1 was always enhanced,that of tubes No.2~4 was firstly enhanced and then weakened,and that of tubes No.5~7 was always weakened.In addition the peak values of tubes No.1~4 occurred at larger heat flux.

关 键 词：R134A 降膜蒸发 水平管 

分 类 号：TK124[动力工程及工程热物理—工程热物理]