中文摘要：

为了研究稀疏气固两相流动中颗粒间的碰撞行为及其对颗粒扩散的影响,对三维两相湍流射流进行了直接数值模拟。其中对流场控制方程的求解采用有限容积法和分步投影算法,对颗粒的跟踪采用拉格朗日方法,对颗粒间的碰撞采用硬球模型模拟。结果发现,在流场中局部浓度较高的区域颗粒碰撞频繁发生;受局部富集效应和湍流输运作用两方面的影响,颗粒的平均碰撞次数并不是随着Stokes数的增加呈现简单的线性增加,而是在Stokes数为0.1附近存在一个极值;考虑颗粒间的碰撞作用以后,颗粒的分布更加均匀,沿横向和展向的扩散也都有所增加。

英文摘要：

To study the inter-particle collision behavior and its effects on particle dispersion in the dilute gas-solid flows, a three-dimensional two-phase turbulent jet was investigated by direct numerical simulation （DNS） . A finite volume method and a fractional-step projection algorithm were used to solve the governing equations of gas phase and a Lagrangian method was used to trace the particles. A deterministic hard-sphere model was used to simulate inter-particle collision. It was found that interparticle collision occurred frequently in the local regions with a higher particle concentration. The variation of average inter-particle collision number with Stokes number was not simple linear under the influence of local accumulation and turbulent transport effects. At St = 0. 1, average inter-particle collision number reached a peak value. Furthermore, particle distribution was more uniform when considering the effect of inter-particle collision, and the dispersion of the particles also increased in the lateral and spanwise directions.