水平管内水蒸汽冷凝换热特性的数值模拟

摘要

对水蒸汽在内径为8 mm的水平圆管内，不同管壁温度、蒸汽流速、压力和入口过热度下的冷凝过程，采用通用CFD软件Fluent 13．0中的Mixture模型，结合UDF编程对水平管内冷凝物理模型进行数值模拟。通过分析相应的冷凝液分布云图、体积分数和局部换热系数的变化曲线，得出蒸汽在水平管内冷凝换热系数与壁温、蒸汽流速、压力和入口过热度的变化规律。并将模拟结果与实验测试结果进行了对比，得出模拟结果比计算值偏高约30％。%By adopting the Mixture Model in CFD software Fluent 13.0 combined with UDF procedure,the numerical simulation was carried out that water vapor condensates inside horizontal tubes which diameter is 8 mm,under different wall temperatures,va-por velocities,pressures and inlet superheats.By analyzing the condensation liquid contour,void fraction and local heat transfer coefficient at different points,the rules are obtained that the condensation heat transfer coefficient changes with the wall tempera-tures,vapor velocities,pressures and inlet superheats.The comparison is done between the simulation result and the experimental results and it shows that the simulation value is larger than the experimental one by 30%.