液固循环流化床预分布器附近流体动力学的数值研究

在液固循环流化床(LSCFB)内,分别以水、玻璃珠为液相和固相,应用2种不同结构的分布器,在室温常压下,考察了分布器结构对预分布器区及换热管内流体动力学的影响。利用商用计算流体力学(CFD)软件Fluent 6.2,选用欧拉模型(Eulerian),系统研究了不同分布器结构和不同表观液速对换热器的预分布器区固体颗粒和局部液体速度径向分布的影响。模拟结果表明:应用变孔径预分布器与均匀孔径预分布器相比,变孔径预分布器能更好地改善固体颗粒和局部液体径向速度分布的均匀性;在低表观液速下,固含率径向分布的计算值与实验值吻合良好,误差随表观液速增大而增大。

Numerical Simulation on Hydrodynamics in Pre-distributor Region of Heat Exchanger in Liquid-solid Circulating Fluidized Bed

A liquid-solid circulating fluidized bed(LSCFB) reactor was employed to investigate systematically the effect of different distributor structures on fluid hydrodynamics in pre-distributor region and heat exchanger under room temperature and atmospheric pressure with water and glass beads as liquid and solid phases,respectively.The CFD code Fluent 6.2 was adopted to simulate the effect of two different structures of distributor and superficial liquid velocities on the radial profiles of solid velocity and local liquid velocity in the pre-distributor region of a GLSCFB using Eulerian multiphase model.The computational results showed that the radial velocity profiles of solid particles and local liquid phase were more uniform using distributor with non-uniform pore diameters than that using distributor with uniform pore diameters.The numerical simulation results for the radial profile of solid holdup agreed well with the experimental data at low superficial liquid velocity.However,larger error occurred at high superficial liquid velocity.