FLOW BOILING OF NATURAL REFRIGERANTS IN HORIZONTAL MINICHANNELS PART 2: TWO-PHASE FLOW BOILING HEAT TRANSFER
Experiments of convective boiling heat transfer in horizontal minichannels with R-744 and R-290 was performed. The test sections were made of stainless steel tubes, uniformly heated by applying electric current directly to the tubes. The inner tube diameters of the test section were 1.5 mm and 3.0 mm with heated lengths of 1000 and 2000 mm. Experiments were performed at inlet saturation temperature ranges from -10 to 10℃, mass flux ranges from 50 to 600 kg/m2s and heat flux from ranges of 5 to 40 kW/m2. The current study showed that the heat transfer coefficient was generally higher with higher heat flux and smaller tube diameter. Nucleate boiling heat transfer contribution was predominant in small channel and higher at low quality region. The refrigerant properties of surface tension, liquid-vapor density and viscosity had a significant effect on heat transfer coefficient. Laminar flow appeared in flow with minichannels. The experimental results were compared against several existing heat transfer coefficient prediction methods. A new boiling heat transfer coefficient correlation based on the superposition model developed.
K.I.CHO A.S.PAMITRAN J.T.OH H.K.OH
Graduate School, Chonnam National University, Yeosu, Chonnam, South Korea Dept. of Refrigeration and Air Conditioning Engineering, Chonnam National University, San 96-1,Dundu Dept. of Refrigeration and A/C Engineering, Pukyong National University, Busan, South Korea
国际会议
The 22nd International Congress of Refrigeration(第22届国际制冷大会)
北京
英文
2007-08-21（万方平台首次上网日期，不代表论文的发表时间）