含不凝性气体冷凝对流传热传质过程的数值模拟

Numerical Simulation of the Heat and Mass Transfer Process of Convective Condensation With Non-Condensable Gas

含不凝性气体冷凝对流换热过程是核能及其它能源领域中的重要物理现象。目前对含不凝性气体冷凝对流换热的研究多局限于实验方法,且实验结果差别较大。本文用数值计算方法模拟了管内含不凝性气体冷凝对流换热过程,并与实验结果进行了对比,误差约为30%～40%。对对流传热传质过程的数值分析表明,纯对流换热约占总换热量的15%,冷凝换热约占总换热量的85%。由于壁面凝结的抽吸作用,在壁面附近产生了垂直于壁面的速度分量,使对流换热增强约100%～200%。

Convective condensation with non-condensable gas is an important phenomenon in nuclear and other energy area. Present investigations about convective condensation with non-condensable gas are mostly experiments, and the experimental results varied a lot. In this paper, convective condensation with non-condensable gas in a tube is numerically simulated. The simulation results are compared with experiments. The discrepancy between the numerical and experimental results is about 30%-40%. Analysis of the numerical results shows that, pure convection contributes to 15% of the total heat transfer rate, while condensation contributes to 85% of the total heat transfer rate. There appears velocity perpendicular to the tube wall due to the suction effect caused by condensation, this enhances the pure convective heat transfer 100%-200%.