EVAPORATION HEAT TRANSFER COEFFICIENTS OF R417A IN HORIZONTAL SMOOTH AND MICROFIN TUBES
An experimental investigation of evaporation for R417A in horizontal smooth and microfin tubes has been carried out with evaporation temperature between 0 and 5.5℃, mass flow rates between 176 and 344 kg·m-2.s-1, heat fluxes between 11 and 32 kW·m-2, and vapor qualities between 0.2 and 1. The heat transfer characteristics of R417A were compared with R22, it indicates that the enhancement is more efficient on pure refrigerants than non-azeotropic refrigerant mixtures using the same enhanced surface. And the heat transfer coefficients of R417A inside different tubes were compared, the enhancement mechanism of inner grooved tube on evaporation heat transfer were analyzed. Based on the experimental results of R417A, a new microfin model was suggested. The comparison of calculations with the experimental results indicated that the new model offered a much better agreement with the experimental results with the reducing average deviation by 30％-50％ than the model by Cavallini.
Xiaoyan ZHANG Xingqun ZHANG Xiuling YUAN
School of Energy and Power Engineering, Xi an Jiaotong University,Xi an, 710049, P. R. China;Schoo School of Energy and Power Engineering, Xi an Jiaotong University,Xi an, 710049, P. R. China
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）