水平冷凝管在水膜作用下稳态传热数值模拟

Numerical Simulation of Steadystate Heat Transfer in Horizontal Condensing Tube under Water Film

本文利用EES软件编制了水膜作用下水平冷凝管的稳态分布参数模型,研究了冷凝管长度,冷凝温度对出口干度,换热量和管内换热系数的影响。计算得出:冷凝管出口干度随着管长的增加不断减小。当制冷剂质量流量从0.0044 kg/s增加到0.0078 kg/s时,冷凝管长度增加35.7%,才能使出口干度达到0。管内平均换热系数随冷凝管长度增加基本不变。换热量随冷凝管长度增加先不断增大,后增加趋势变缓。冷凝温度越高冷凝管出口干度越小。换热量随冷凝温度升高而增大,制冷剂低质量流量下冷凝温度对换热量的影响比高质量流量下的影响小。与换热量相反,管内平均换热系数随冷凝温度的升高而减小。

The EES software is used to develop the steadystate distribution parameter model of horizontal condensing pipe under the action of water film,and the influences of condensing pipe length and condensing temperature on outlet dricity,heat transfer and heat transfer coefficient inside the pipe are studied.The results show that the outlet dryness of the condensing pipe decreases with the increase of the pipe length.When the refrigerant mass flow rate increases from 0.0044 kg/s to 0.0078 kg/s,the length of the condensing tube increases by 35.7%,so that the outlet dryness reaches 0.The average heat transfer coefficient of the tube is basically unchanged with the increase of the length of the condensing tube.As the length of the condensing tube increases,the heat transfer first increases and then the increasing trend slows down.The outlet dryness of condensing pipe decreases with the increase of condensation temperature.The heat transfer increases with the increase of the condensation temperature,and the influence of the condensation temperature on the heat transfer at low mass flow rate is less than that at high mass flow rate.In contrast to heat transfer,the average heat transfer coefficient decreases with the increase of condensation temperature.