【摘要】 目前超临界水传热数值程序中使用的湍流模型都是针对亚临界压力下常物性开发的,未考虑密度脉动。超临界水的物性随温度变化显著,密度脉动对湍流模型的贡献很大,不可忽略。本文建立了考虑密度脉动的模拟方法,模拟方法中同时考虑了热膨胀系数的脉动。将建立的密度脉动模型用于AKN湍流模型中,并采用实验数据进行验证评价。评价结果表明,考虑密度脉动的湍流模型模拟得到的结果与实验值符合得更好。建议在以后的超临界水传热的湍流模拟中考虑密度脉动。更多还原

【Abstract】 The turbulence model used in the current numerical simulation for heat transfer to supercritical water is developed based on theory and experimental data at subcritical pressures and the density fluctuation is neglected.However,the thermophysical properties of supercritical water vary significantly as temperature approaches the pseudo-critical temperature so that the density fluctuation should not be neglected for its important role in the turbulence model.The simulation method considering density fluctuations was developed,in which the thermal expansion coefficient fluctuation was also taken into account.The density fluctuation was implemented in the AKN turbulence model and the model prediction was assessed using experimental data.The validation results show that the predicting results agree better with experimental data.It is recommended that the density fluctuation should be taken into account in future turbulence simulation of heat transfer for supercritical water.更多还原