用颗粒相双尺度二阶矩湍流模型模拟突扩两相流动

基于将颗粒脉动分成湍流引起的大尺度脉动和颗粒间碰撞产生的小尺度脉动的概念，应用单相流动多尺度湍流模型方法，从双流体模型出发，推导和封闭了颗粒的双尺度脉动雷诺应力方程、大尺度脉动能量传递率方程、小尺度脉动耗散率方程和两相脉动关联方程，用统一的湍流模型方法构造了包含颗粒两类脉动的新的颗粒双尺度二阶矩两相湍流模型．用该模型对突扩管内的两相流动进行了数值模拟，并和单尺度的二阶矩两相湍流模型进行了比较，计算结果和实验数据吻合较好，比单尺度的二阶矩两相湍流模型的计算结果有所改进．

Simulation to Sudden-Expansion Two-Phase Flows with Two-Scale Second-Order Moment Particle Turbulence Model

A two-scale second-order moment particle turbulence model accounting for interparticle collision is developed based on the concept that the particle fluctuation can be divided into large-scale one due to turbulence and small-scale one due to collision with a unified treatment. Adopting the multiple scale of single-fluid method and two-fluid model, the particle Reynolds stress equation for two-scale fluctuation, the energy transfer rate equation for large-scale fluctuation, the turbulent kinetic energy dissipation rate equation for small-scale fluctuation, and the gas-particle velocity correlation equation for two-scale fluctuation are all derived and closed. The presented model is employed to simulate gas-particle flows in a sudden-expansion chamber, and the simulated results coincide well with the experimental ones. It is also demonstrated that the presented two-scale model is with higher calculating accuracy than the single-scale model.