基于拉氏概率密度的两相湍流二阶矩模型

A SECOND-ORDER MOMENT TWO PHASE TURBULENCE MODEL BASED ON THE LAGRANGIAN PDF

用颗粒运动的拉氏分析和PDF方法 ,改进了颗粒相的二阶矩模型。由拉氏两相运动的随机微分方程出发 ,采用随机过程分析和信号分析法得到湍流两相流动的PDF输运方程 ,双流体模型方程和两相脉动速度相关的基本模式的封闭式 ,和用其它方法导出的方程与封闭式的结果一致 ,对封闭式作了重要的改进 ,在分析颗粒轨道上的流体湍流作用时间时 ,全面地引入拉氏分析的轨道穿越效应、惯性效应。

Using the Lagrangian analysis of particle motion and PDF(Probability Density Distribution Function)method,an improved the second order moment model of particle phase is proposed.Based on the Lagrangian stochastic two phase motion equations, using the stochastic process analysis and the signal system analysis, the obtained particle phase PDF transport equation,the two fluid model equations and the basic version of two phase fluctuation velocity correlation are in agreement with those obtained by other investigators.However,significant improvement is made for the closure model.The crossing trajectory effect,continuity effect,inertia effect and the anisotropic turbulence have been taken into account to simulate the interaction time between the particle and the fluid turbulence seen by the particles.