空间发展湍流气粒两相平面混合层的大涡模拟与统计

本文对空间发展的湍流气固两相平面混合层流动进行了大涡模拟研究,其中气相亚网格尺度（SGS）使用结构函数模型,气相控制方程组采用SIMPLE方法求解,固体颗粒运动用拉格朗日方法计算。计算结果正确重现了流体涡结构的卷起、合并和破碎过程,以及小尺寸颗粒在涡边缘（低涡度区）的局部富集现象。对直径分别为42μm、72μm和135μm分别进行了模拟,并将统计结果和实验测量结果（Hishida　et　al1]）比较,表明两者的平均速度吻合很好,但颗粒数密度和脉动速度存在较明显的差异,因此有必要对亚网格应力和颗粒之间的耦合作用以及拟序结构的三维性对颗粒运动的影响开展深入研究。

LARGE EDDY SIMULATION OF GAS-PARTICLE TURBULENCE IN A SPATIALLY DEVELOPING PLANAR MIXING LAYER

Turbulent gas-particle flow in a spatially developing planar mixing layer is investigated by 2-D large eddy simulation, where subgrid-scale stress of gaseous species is modeled by structural function model. The governing equation of continuum phase is solved under SIMPLE scheme, while the particle motion is calculated in Lagrangian frame. The numerical result reproduces the rollup, pairing and breakdown process of vortices, and preferential concentration of specific particles at low vorticy area. Comparison of predicted results and experiments(Hishida et al~(1])) show LES can well predict particle average velocity, while apparent discrepancy exist for particle number density and fluctuation velocity. Further investigation on the effects of SGS model and three-dimensionality of coherent structure on particle motion are needed.