喷动床内气固两相流动进口旋流效应数值模拟

Numerical simulation of inlet swirling effects on gas-solid two-phase flow in a spouted bed

为了研究喷嘴进口气体旋流效应对喷动床内气固两相流动特性的影响规律,采用数值模拟方法进行研究分析。通过欧拉-欧拉双流体模型和颗粒动力学理论对气固两相流动进行模型处理,分别对常规喷动床及带旋流器喷嘴喷动床进行模拟分析与对比。研究表明:喷嘴进口气体旋流效应显著地强化了喷动床内颗粒的径向运动,能有效消除柱锥区的颗粒堆积现象,扩大了低床层区气体喷射区的影响范围,增加了喷动床内气体的湍动能值,从而提高喷动床内颗粒处理的整体效率。存在最佳η(旋流器内径与外径比值)值,即η为0.526时,旋流气体对喷动床环隙区内颗粒堆积的消除作用及气体湍动能值的提升最为显著,同时旋流器喷动床的总体压降达到了峰值。

In order to deeply understand swirling flow effects in spouted beds on gas-solid two phase flow,numerical simulation was used in this study.The Euler-Euler two-fluid model and particle dynamics theory were applied for studying the gas-solid two-phase flow model.Simulation and comparison of a conventional spouted bed and a spouted bed with a swirling flow generator were carried out.The simulation results show that the radial motion of particles in the spouted bed is significantly enhanced by the flow effect of gas swirl at the nozzle inlet,which can effectively eliminate the accumulation of particles in the cylinder-cone zone,and expand the influence range of the spout zone at the low bed.The turbulent kinetic energy of gas in the spouted bed is enhanced by the swirling flow of gas phase,which can improve the overall efficiency of particle treatment in the spouted bed.The effect of swirling gas on elimination of particle accumulation and gas turbulence energy in the annulus region of the spouted bed becomes the most significant at an optimal value of η=0.526.Meanwhile,the overall pressure drop of the spouted bed with swirling flow reaches the peak value.