含空气的蒸汽冷凝传热模型研究

Study on Steam/Air Condensation Heat Transfer Model

建立含空气的蒸汽在竖直圆管自然对流条件下外表面冷凝传热模型。建模过程中,考虑到部分蒸汽未到达交界面发生液化形成雾,强化传热,对自然对流传热系数进行修正;计算冷凝热导率时,积分算法中考虑混合气体的密度在扩散边界层内的变化。结果表明:96%的预测结果与Dehbi实验结果的偏差在15%内,与Anderson实验结果的最大偏差为16.8%;将本文模型与已有模型对比,新模型相对另外2种模型具有更高的精度。

Under the natural convection condition, a heat transfer model of steam/air condensation on the vertical tube external surface is built. In the modeling process, considering that some steam which liquefies when not reaching the gas-liquid interface can enhance heat transfer, the natural convective heat transfer coefficient is corrected; when calculating the condensation heat conductivity, the integration algorithm considers changes of the gas mixture density in the diffusion boundary layer. The results show that the deviation between predicted values of the model and Dehbi＇s experiment results is less than 15%, and the maximum deviation against the Anderson＇s experimental results is 16.8%.Compared the present model with the existing models, it is found that the new model has higher precision than the other two old models.