内置转子圆管管内沸腾强化传热数值模拟研究

Numerical simulation of the boiling heat transfer performance of a circular tube with inserted rotors

利用Fluent软件中欧拉多相流模型下的Rensselaer Polytechnic Institute(RPI)沸腾模型对内置单元组合转子换热管和光管在过冷沸腾工况下的传热过程进行数值模拟,得到换热管内汽相分布、速度场、努赛尔数以及进出口压降等参数,并通过综合评价因子(PEC)对内置转子换热管的综合传热性能进行评价。结果表明:加装了组合转子后,管内流体由单一的轴向运动变为复杂的螺旋运动;在入口流速0.1~0.5 m/s的模拟范围内,随着入口流速的减小,内置螺旋三叶片转子换热管的汽相体积分数比光管提高2.7%~25.8%,努塞尔数提高了约8.1%~10.79%;在不同入口流速下螺旋三叶片转子和低流阻转子的PEC值均大于1,内置低流阻转子换热管的汽相体积分数比光管提高1.13%~13%,努塞尔数提高约3.6%~8%。螺旋三叶片转子和低流阻转子均具有强化传热效果,且螺旋三叶片转子的强化传热效果要优于低流阻转子。

A Rensselaer Polytechnic Institute(RPI)boiling model based on Euler multiphase flow model in Fluent software has been established to simulate the boiling heat transfer processes in a circular tube with inserted rotors and a plain tube.Parameters such as vapor volume fraction,Nu number,inlet and outlet pressure drop were obtained.Performance evaluation criteria(PEC)were introduced to evaluate the comprehensive heat transfer performance of the tube with inserted rotors.The simulations show that in the range of inlet velocity from 0.1 m/s to 0.5 m/s,as the inlet velocity decreases,the vapor volume fraction of the circular tube with inserted rotors increases by 2.7%-25.8%compared with the plain tube.The Nu number was 8.1%-10.79%higher than for the plain tube and the PEC was greater than one,which indicates that insertion of the rotors affords an enhanced heat transfer performance.