文献类型：期刊文献

英文题名：Experimental study on condensation of steam/air mixture in a horizontal tube

作者：Ren, Bin[1];Zhang, Li[1];Xu, Hong[1];Cao, Jun[1];Tao, Zhenyu[1]

机构：[1]E China Univ Sci & Technol, State Key Lab Chem Engn, Sch Mech & Power Engn, Shanghai 200237, Peoples R China

年份：2014

卷号：58

起止页码：145

外文期刊名：EXPERIMENTAL THERMAL AND FLUID SCIENCE

收录：;EI(收录号：20151100621238);WOS:【SCI-EXPANDED(收录号:WOS:000341674900016)】；

语种：英文

外文关键词：In-tube condensation; Horizontal tube; Noncondensable gas; Flow regime; Heat transfer correlations

摘要：The effect of noncondensable gas on condensation heat transfer inside horizontal tubes was investigated experimentally. Air was used as the noncondensable gas. The effects of inlet noncondensable gas mass fraction, inlet gas mixture mass flux and inlet pressure on overall heat transfer performance were analyzed. Moreover, local heat transfer performance was investigated by comparing centerline temperatures and local heat transfer coefficients. The results showed that the overall heat transfer coefficient decreased as inlet noncondensable gas fraction increased. Increasing inlet mass flux could enhance the heat transfer rate and overall heat transfer coefficient. Furthermore, the heat transfer rate showed an increasing trend, whereas the overall heat transfer coefficient decreased with increase of inlet pressure. The local heat transfer coefficient decreased along the condenser tube due to the decrease of gas mixture Reynolds number and the increase of liquid film thickness and local air fraction. For stratified flow, the local heat transfer coefficient at the top part was higher than that at the bottom owing to the asymmetrical liquid film. However, this gap gradually decreased along the tube, especially at higher inlet noncondensable gas fraction. Finally, two correlations respectively for stratified flow and annular flow regimes were developed, using the modified Froude number as the indicator of transition from stratified to annular flow. (C) 2014 Elsevier Inc. All rights reserved.