贴体坐标系下喷动床内气固两相流体动力特性的数值模拟

采用稠密固相动力-摩擦应力模型,建立喷动床内气固两相双流体模型．应用贴体坐标系使得计算网格与喷动床的倒锥体边界相一致．通过数值模拟获得喷动床内喷射区、环隙区和喷泉区内颗粒速度及浓度分布．计算结果表明,喷泉区具有强烈的气固两相质量和动量交换．当倒锥体倾斜角度达到60°,在射流入口处形成一瓶颈．研究表明颗粒间滑动-滚动摩擦应力对环隙区颗粒流动具有明显的影响．

Gas-Solid Flow Simulations in Spouted Beds on Body-Fitted Coordination

A gas-solid two-fluid model is presented in which the kinetic-frictional rheological model for dense assemblies of solids is incorporated in the simulation for spouted bed. This model treats the kinetic and frictional stresses of particles ad-ditively. The body fitted coordination is used to make the grids best fit the outh'ne of a conical contour of the base in the spouted bed. The typical flow patterns in spouted beds were obtained, i. e. , the spout, the fountain and the annular zones, and clearly indicated. Effects of operating conditions and geometrical dimensions of conical contour on partical velocity and concentration in the spout, annulus and fountain are determined. Our simulations showed that as the inclined angle decreases, the diameter of the spout increases. For an inclined angle of 60?and greater, there is a neck near the inlet of spouted beds. Simulations of particle concentration and velocity distributions in a spouted bed revealed that the frictional stresses were significant effect on the flow of particles in the annulus.