【摘要】 实验研究水平微肋管内R290的两相流凝结换热特性,在内径为4.3 mm,长度为900 mm的铜管内,测得R290在质流密度180—300 kg/(m~2·s)、饱和温度40—55℃、热流密度3—10 kW/m~2以及干度0.9—0.1范围内的凝结换热系数;分析了质流密度、饱和温度、热流密度以及干度对R290凝结换热性能的影响。结果发现:凝结换热系数随质流密度、热流密度的增大而增加,随饱和温度的升高而减小;随着R290的凝结液化,干度减小,其凝结换热系数也随之减小,仅在热流密度过大时出现先增后减现象。并分别采用4种经典的凝结换热关联式预测R290的凝结换热系数,对比实验结果得出Chang等和Yu等的预测精度比较高。更多还原

【Abstract】 The condensation heat transfer characteristics of R290(propane) in a horizontal micro-fin copper tube with 4.3 mm inner diameter,900 mm length were investigated experimentally. The coefficients were analyzed respectively at mass flux of 180-300 kg/(m~2·s),saturated temperature of 40-55 ℃,heat flux of 3-10 kW/m~2,and the quality ranged of 0.9-0.1.The results show that condensation heat transfer coefficients increase with the increasing of mass flux and heat flux while decrease with increasing saturation temperature. The condensation heat transfer coefficients generally decrease except that it increases at first but then decreases under excessive heat flux with the vapor quality decreasing. Finally, comparing the experimental coefficients with the data of condensation heat transfer coefficients of R290 got by four classical correlation equations selected in the paper, it can be concluded that those two equations respectively suggested by Chang and Yu are high accuracy.更多还原