在螺旋套管冷凝器内R417a凝结换热性能的实验研究

Experimental Study on Condensation Heat Transfer Performance of R417a in Spiral Casing Condenser

中文关键词: R417a 螺旋套管  逆流换热 凝结换热

英文关键词: R417a  helical casing  countercurrent heat transfer  condensation heat transfer

中文摘要:

      在空气源热泵热水器中,使用混合型制冷工质R417a,冷凝器采用螺旋套管换热器且套管环形空间内制冷剂与内管中的水逆流换热。对在不同工况下,环形通道内R417a的凝结换热特性进行实验研究和理论分析。本实验的工况范围为：水的体积流量为0.6～1.00 m₃/h,水的流速为0.58～0.98m/s,冷凝器进水温度为20.0～55.0℃。实验结果表明：环境温度为15.0℃,螺旋套管内R417a的凝结换热系数随冷凝饱和温度的升高而减小,局部凝结换热系数随干度的增大而增大。当冷凝器进水流量为0.60 m₃/h,饱和冷凝温度由40.0℃增加至60.0℃时,冷凝器制冷剂侧凝结传热系数从3839.0W/(m₂.K)减小至2372.0W/(m₂.K),约减少了38.1%。

英文摘要:

      In the air source heat pump water heater, the mixed refrigeration agent R417a is used. The condenser adopts the spiral casing heat exchanger and the refrigerant in the annular space of the casing transfer heat with the water in the inner tube in counter manner. The experimental study and theoretical analysis of the condensation heat transfer characteristics of R417a in annular channel under different working conditions were carried out. The working conditions of this experiments are as follows: the volume flow rate of water is 0.6 ~ 1.0 m₃ / h, the flow speed of water is 0.58 ~ 0.98m / s, and the temperature of condenser is 20.0 ~ 55.0 ℃. The experimental results show that the condensation heat transfer coefficient of R417a in the spiral casing decreases with the increase of the condensation saturation temperature, and the local heat transfer coefficient increases with the increase of the dryness. When the inlet flow rate of the condenser is 0.60 m₃ / h and the saturated condensation temperature is increased from 40.0 ℃ to 60.0 ℃, the condensation heat transfer coefficient of the condenser side is reduced from 3839.0W / (m₂ ? K) to 2372.0W / (m₂? K ), about a decrease of 38.1%.