AN EXPERIMENTAL STUDY ON HEAT TRANSFER AND PRESSURE DROP CHARACTERISTICS OF CARBON DIOXIDE DURING GAS COOLING PROCESS IN A HELLICALLY COILED TUBE
The heat transfer coefficient and pressure drop during gas cooling process of CO2 (R744) in a helically coiled copper tube with the inner diameter of 4.55 and outer diameter of 6.35 mm were investigated experimentally. The main components of the refrigerant loop are a receiver, a variable-speed pump, a mass flow meter, a pre-heater and a helically coiled type gas cooler (test section). The refrigerant mass fluxes are varied from 200 to 800 kg/m2s and the inlet pressures of gas cooler are 7.5 to 10.0 MPa. The heat transfer coefficients of CO2 in a helically coiled tube are higher than those in a horizontal tube. The pressure drop of CO2 in the gas cooler shows a relatively good agreement with those predicted by Ito’s correlation developed for single-phase in a helically coiled tube. The local heat transfer coefficient of CO2 agrees well with the correlation by Pitla et al. However, at the region near pseudo-critical temperature, the experiments indicate higher values than the Pitla et al. correlation. Therefore, various experiments in helically coiled tubes have to be conducted and it is necessary to develop the reliable and accurate prediction determining the heat transfer and pressure drop of CO2 in a helically coiled tube.
H.K.OH C.H.SON M.J.JEON J.T.OH
Department of Refrigeration and Air-Conditioning Eng., Pukyong National University, San 100,Yongdang Department of Refrigeration and Air-Conditioning Eng., Graduate School, Pukyong National University, Department of Refrigeration Engineering, Chonnam National University, San 96-1,Dundeok-dong, Yosu, 5
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）