各向异性颗粒PDF输运方程及其颗粒湍流扩散

Turbulent Particle Dispersion Modeling with PDF Equation Based on Langevin Equation of Fluid Velocity

摘要: 根据Minier的模型,获得颗粒所见流体脉动速度的朗之万模型,并推导颗粒所见流体湍流脉动速度自关联函数,该函数具有各向异性的特征,进一步由流体脉动速度朗之万模型和颗粒运动方程获得相应的颗粒PDF输运方程.为描述在网格生成湍流中的颗粒扩散运动,将颗粒PDF输运方程作相应的简化,获得一个具有颗粒湍流各向异性的解析解,将方程的解与Wellsand Stock的颗粒湍流扩散实验结果进行比较,获得了很好的结果.揭示了具有各向异性特征的颗粒PDF输运方程的优越性.

Abstract: A Langevin equation of fluctuating velocity of fluid ‘seen’ by particle is simplified in Minier's model.Autocorrelation of turbulence fluctuating velocity is obtained,which has non-isotropic property.Corresponding PDF model of particle is obtained and a simplified form is used to predict turbulent particle dispersion in grid-generating turbulence flow.PDF model is solved analytically and solutions are compared with experimental results of Wells and Stock.