圆管内超临界水传热恶化数值模拟及模型评价

Model Evaluation and Numerical Analysis of Supercritical Water Heat Transfer Deterioration in Circular Tubes

采用计算流体力学(CFD)方法对圆管通道内超临界水的传热恶化特性进行数值模拟研究,将现有模型对超临界条件计算的适用性和可靠性进行了评估。计算结果表明,在低质量流速条件下,传热恶化发生时流道内将会出现M型的速度分布,最大速度处的湍动能明显减小;在高质量流速条件下,传热恶化时各物性参数中热导率对其传热特性有明显的影响。模型评估结果表明,本研究中SST模型能够用于高质量流速条件下传热恶化的计算。

This paper presents a numerical simulation of the heat transfer deterioration of supercritical water in circular tubes,and evaluates the validity and reliability of the existing CFD model under super-critical condition.The calculation indicates that when the heat transfer deterioration occurs at low mass flux condition,the velocity profile behaves M shaped in the radial direction,and at the place of maximum velocity,the turbulent kinetic energy decreases evidently.At high mass flux condition,the result shows that the varia-tion of thermal conductivity have great effect on the heat transfer.The mode evaluation indicates that SST mode can be used to calculate the heat transfer deterioration at high mass flux conditions.