蒸发式冷凝器异型扁管性能分析及数值模拟

Performance Analysis and Numerical Simulation of Evaporative Condenser with Special-shaped Flat Tube

针对目前蒸发式冷凝器采用的圆管、椭圆管、弹形管管型的不足,设计开发了新型异型扁管的管型结构,为验证其优良性能,运用FLUENT软件对4种管型管束内强制对流空气进行数值模拟,建立了管束流场的数学模型,采用求解压力耦合方程组的半隐式方法（SIMPLE）进行迭代计算求解,在进口流速为1.5~3.9 m/s范围内分别进行了计算,运用Tecplot10后处理软件直观表征空气的速度场、温度场、压力场,给出了压降损失随空气流速变化关系曲线.数值模拟结果表明,新型异型扁管和其他3种管型相比,压降约降低30%、21%及15%,同时出口截面空气平均温度有所增加.

Considering the shortages of current used tube in the evaporative condenser such as circular tube,oval tube and bullet tube,the paper designed a new kind of tube type called special-shaped flat tube with good performance.By using the FLUENT software,a numerical simulation research on the forced convection air flow of 4 kinds of tube bundles which were circular tube,oval tube,bullet tube and special shaped flat tube was conducted.The mathematical model of the tube bundle flow field was established.Our implementation incorporated a SIMPLE-based semi-implicit solution algorithm that was applied to iterating calculation.Inlet velocity from 1.5 to 3.9 m/s was calculated separately.The data of simulation was processed by Tecplot 10,which provided a direct illustration of the velocity,pressure and temperature fields of the flowing air in the tube bundles.The relationship curve of the pressure changing with the air velocity was also presented.The result demonstrated that comparing with the other 3 tube types,the average pressure drop of the new tube type was 30%,21% and 15% smaller and the average air temperature in the outlet cross section was higher.