【摘要】 对替代制冷剂R-134a在水平直管和螺旋管内的凝结换热特性进行了实验研究。在三个不同的冷凝温度(35℃、40℃和45℃)、制冷剂R-134a的质量流量变化范围为100~400kg/(m2.s)和制冷剂的干度范围为0.1~0.8的条件下,实验得到了R-134a在水平直管和螺旋管内的凝结换热系数随R-134a的质量流量和干度的变化关系,并将水平直管和螺旋管内的凝结换热特性数据进行了对比。实验结果表明,R-134a在螺旋管内的凝结换热系数比直管的大4%~13.8%。更多还原

【Abstract】 The characteristics of condensation heat transfer for R-134a in horizontal straight tubes and helical tubes were experimentally investigated.The experimental were carried out at three saturation temperatures(35℃,40℃ and 45℃) with the refrigerant mass flux from 100 to 400 kg/(m2·s) and the vapor quality from 0.1 to 0.8.The effects of vapor quality and mass flux of R-134a on the condensation heat transfer coefficient were obtained,and the heat transfer characteristics for straight and helical tubes were compared.The results indicate that the condensation heat transfer coefficients in the helical tubes were 4%-13.8% higher than those in the straight tubes.更多还原