倾斜热管湍流床的气固流动特性

Gas-solid flow characteristics in a turbulent fluidized bed with inclined heat pipes

为了探明间壁式流化床换热器内热管对气固流动状态的影响,采用欧拉双流体模型,并应用能量最小多尺度(energy minimization multi-scale, EMMS)曳力模型,对可实现2种物性相近催化剂热管间壁换热的湍动流化床流动特性进行模拟研究。结果表明:通过与实验数据进行比较,证明模型是有效的;比较热管对床内固含率轴向分布的影响,发现热管的设置可减小气泡尺寸、有效降低颗粒被夹带量;热管对固含率的影响主要位于热管末端,其仅存在于热管所在区域,且随着径向位置靠近隔板逐渐减小;沿热管轴向存在隔板影响区和主换热区,主换热区随着轴向高度的增加而减小,随着表观气速的增大而增大。

In order to investigate the effect of heat pipes on gas-solid flow state in the fluidized bed heat exchanger with heat pipes,the Euler two-fluid model with the energy minimization multi-scale(EMMS)drag force model was employed to investigate turbulent fluidized bed with tilted heat pipes,which could realize the efficient heat transfer between two catalysts with similar physical properties by heat pipes.The results show that the validity of the model is verified by comparing with experimental data.Compared with the effect of heat pipe on the axial distribution of solids holdup,it is found that the heat pipe can reduce the bubble size and the particle entrained amount.The influence of heat pipe on solids holdup is mainly located at the end of heat pipe in the radial direction and in the axial direction where the heat pipe is located.And the solids holdup decreases gradually as the radial position is close to the baffle.The size of main heat transfer zone decreases with the increasing of axial height and increases with the increasing of superficial gas velocity.