摘要
在系统压力p=0．41～0．63MPa，过冷度△T_sub=6～12℃，热流密度q=0．11～10．90kW．m～，质量流量G=-147～249kg·m-2·s-的条件下，对卧式螺旋管内R134a过冷流动沸腾的换热特性进行了实验研究。分析过冷沸腾条件下螺旋管不同截面上的壁温分布表明：截面周向壁温呈现不均匀分布；螺旋管的截面位置对部分过冷沸腾向充分发展过冷沸腾的转变产生了很大影响。分析了各实验参数对充分发展过冷沸腾换热系数的影响趋势：随着热流密度、系统压力的增大换热系数不断增大；但是，当入口过冷度增大时换热系数却在减小：质量流量对换热系数的影响并不明显。对实验数据进行回归分析，发展了适用于卧式螺旋管内充分发展过冷沸腾换热系数的关联式。
The subcooled boiling heat transfer of R134a in a helical tube was experimentally investigated. The experiments were carried out at pressure ranging from 0.41 to 0.63MPa,＇ subcooled from 6 to12 ℃, heat flux from 0.11 to 10.9 kW·m-2 and mass flux from 147 to 249 kg.m-2·s-1. The wall temperature distribution of a horizontal helical coil was analyzed on the conditions of subcooled boiling. The experimental results indicate that the wall temperature distributions of the cross sections are non-uniform. The location of the cross section was found to has a significant impact on the transition from partial to fully developed subcooled flow boiling. The effects of the boiling heat flux, refrigerant mass flux, system pressure and inlet subcooling of R-134a on the coefficient of subcooled boiling heat transfer were explored in detail. The R134a subcooled flow boiling heat transfer coefficient increases with an increase in heat flux and system pressure. However, raising the inlet subcooling can cause a reduction on boiling heat transfer coefficient. Besides, the mass flux exhibits rather slight effects on heat transfer coefficient. The correlation of subcooled boiling heat transfer coefficient in horizontal helical coil was developed on the basis of regression analysis of experimental data.
出处
《中国电机工程学报》
EI
CSCD
北大核心
2015年第11期2788-2795,共8页
Proceedings of the CSEE
基金
国家自然科学基金项目(51076084)~~
关键词
卧式螺旋管
过冷沸腾
壁面温度
换热系数
关联式
horizontal helical coil
subcooled boiling
wall temperature
heat transfer coefficient
correlation
