关键词: 分离, 颗粒流, 计算流体力学, 颗粒-壁面撞击模型, 非球形颗粒曳力模型

Abstract:

Particle-wall collision and particle-gas interaction have significant influence on the separation performance of the impact separators. The experiments were carried out to study the particle-wall collision behaviors. A particle-wall collision model with average restitution coefficient was proposed. The restitution coefficient and friction coefficient were described as a function of collision angle, and this function varies for different particles. The shape of particles was measured by microscope. The glass beads are very close to sphere, while the coal particles are quite irregular. Thus spherical particle drag force model was adopted for glass beads, and non-spherical particle drag force model was adopted for coal particles. The numerical investigations on the separation performance and gas-solid flow in the plate-type impact separators were conducted with the particle-wall collision model and non-spherical drag force model. The simulation results show good agreements of both overall and grade separation efficiency with the experimental results. The separation prediction of particles with large Stokes number is sensitive to the particle-wall collision model, while that of particles with small Stokes number is sensitive to the particle-gas drag force model.

Key words: separation, granular flow, computational fluid dynamics, particle-wall collision model, non-spherical particle drag force model