摘要
为了研究含空气蒸汽在水平管内强制对流冷凝换热特性,通过实验分析了空气含量及气相流速对局部换热系数的影响;分析了不同空气入口质量分数下,局部换热系数与换热管上、下壁面温度沿换热管轴向的分布规律。结果表明:局部换热系数随空气质量分数的增加而减小,而气相流速的增加会削弱空气对冷凝换热的抑制效果;与纯蒸汽冷凝不同,换热管外下壁面温度会在轴向某一位置后大于上壁面,并且随着入口空气质量分数的增加,该位置逐渐向换热管入口移动;局部换热系数沿轴向变化结果在环状流和波状流条件下存在差异,当空气含量增加时,这种差异会随之减小,使得换热管内局部换热系数轴向变化规律趋于一致。
In order to investigate the characteristics of forced convection condensation heat transfer of steam with air inside a horizontal tube, an experiment was done to analyze the influence of air mass fraction and mix- ture gases velocity on the local heat transfer coefficient. The axial profile of upper and lower wall temperature, and the local heat transfer coefficient along the tube were also analyzed with various mass fractions of inlet air. The results show that the local condensation heat transfer coefficient decreases with the increase of air mass fraction, and that air inhibition of condensation will decrease with increases in mixture gases velocity. Differing from pure steam condensation, the temperature at the external bottom of the tube will become higher than the top at a certain point along the tube, and this point will move closer to the inlet as air mass fraction increases. The axial profile of the local heat transfer coefficient under annular and wavy flow regimes is different and the difference between them will decrease with an increase in air mass fraction, which smooths the whole axial pro- file of the local heat transfer coefficient.
出处
《哈尔滨工程大学学报》
EI
CAS
CSCD
北大核心
2015年第11期1443-1447,共5页
Journal of Harbin Engineering University
基金
国家863计划资助项目(2012AA050906)
关键词
水平管
空气蒸汽混合气体
换热系数
冷凝
实验研究
强制对流
horizontal tube
steam-air mixture
heat transfer convection coefficient
condensation
experimental study
forced
