二次进气角度对流化床接收器中颗粒流动特性的影响

Influence of Secondary Aeration Angle on Particle Flow Characteristics inside Fluidized Bed Particle Receivers

为了探究不同二次进气角度对流化床太阳能颗粒接收器内颗粒流动特性的影响,采用了欧拉-欧拉双流体模型与非均质过滤曳力模型(filtered)耦合的数值计算方法,数值模拟了30°,45°和60°3种二次进气角度下接收器内颗粒浓度及颗粒速度的分布。结果表明:与均匀曳力模型(Gidaspow和Wen-Yu)相比,非均质过滤曳力模型计算结果与实验结果具有较好的一致性;在3种二次进气角度下,颗粒沿径向均呈现出边壁附近的颗粒体积分数高于中心区域的“环-核”非均匀径向分布,且两侧壁面的颗粒流向中心区域形成循环,同时伴随着颗粒团聚现象;相比于二次进气角度30°和60°,当二次进气角度为45°时,二次进气入口截面颗粒分布相对均匀,且不存在颗粒返混回二次进气入口的现象。

In order to investigate the influence of different secondary aeration angles on the particle flow characteristics inside solar fluidized bed particle receivers,a numerical calculation method that couples the Eulerian-Eulerian two-fluid model with a heterogeneous filtered drag force model was employed to simulate the distribution of particle concentration and velocity in the receiver under the three secondary aeration angles of 30°,45°and 60°.The results indicate that compared with the homogeneous drag models(Gidaspow and Wen-Yu),the calculation result filtered drag model agrees well with the experimental result;under the three secondary aeration angles,the particles in the receiver exhibits the"core-annular"heterogeneous radial distribution with dilute center and dense wall in the receiver,and particles on the sidewalls circulate towards the central area,demonstrating significant particle aggregation;when the secondary aeration angle is 45°,compared to the aeration angle of 30°and 60°,the particle distribution on the section of inlet of the secondary aeration region exhibits greater uniformity,without particle back-mixing to the aeration inlet.