深埋风道湿空气凝结数值模拟

Numerical Simulation of Moist Air Condensation in a Deep Tunnel

提出了一种实现空气降温凝结数值模拟的方法,建立了深埋风道传热传湿数学模型,利用FLUENT的用户自定义函数功能,将热质传递关系式转化为相应控制方程的源项,对风道内流动空气热湿耦合传递进行了三维非稳态数值模拟,计算了空气进出口温差、析湿量和传热量,结果表明:凝结起始截面空气平均相对湿度低于90%;热湿耦合作用对空气温湿度变化影响较大,入口空气相对湿度由70%增大到90%时,析湿量和传热量分别增大86.6%和36.8%,出口温降减小2.17℃。为地热能利用研究及地下工程通风温湿度预测奠定了基础。

A numerical simulation methodology is presented to calculate the cooling condensation of moist air via establishment of the heat and moisture transfer mathematical models of air in a tunnel. The air temperature difference between inlet and outlet, the amount of dew, and the heat transfer rate are obtained from the three-dimensional unsteady simulation of coupled heat and moisture transfer of air in the tunnel by adding the heat and mass transfer integral equation to the corresponding control equation as a source term which takes advantage of the user-defined-functions of FLUENT software. Simulation results show that the cross section average relative humidity of air is lower than 90% as condensing begins. Not only heat but also moist influence changes of the air temperature and humidity greatly. Increase of the inlet relative humidity from 70% to 90% results in increase of the amount of dew by 86.6%, the heat transfer rate by 36.8%, and decreases of the temperature drop of air by 2.17 ℃. The simulation lay the foundation for both research of geothermal energy utilization and temperature and humidity predication in underground constructions.