提升管反应器中颗粒浓度径向分布的力学特性

Mechanical Radial Distribution of Particles Concentration in a Riser Reactor

采用空气动力学中的Kutta-Joukowski升力定理分析了提升管内颗粒的受力,得到了Kutta-Joukowski力FK-J的计算公式FK-J=ρg(vg,Z-vp,Z)(?vp,Z/?r)r.根据在大型冷模实验装置上由PV-6D型颗粒密度两用仪测量的局部固含率和颗粒速度径向分布的实验数据,计算了Kutta-Joukowski力在提升管内的分布特征,分析了颗粒循环量、表观气速、轴向位置对其径向分布的影响.结果表明,当无因次半径r/R=0时,FK-J=0,在r/R=0.85时,FK-J最大;FK-J随颗粒循环量增大而增大,表观气速对FK-J的径向分布没有显著影响;在提升管内的充分发展段FK-J的数值明显大于提升管加速区和出口约束区.由实验数据回归出了提升管内FK-J径向分布的经验关联式,计算值与理论值吻合较好.

Based on the Kutta-Joukwski lift force law in aerodynamics, the force on particles is analyzed, and the theoretical method FK-J=ρg（vg,Z-vp,Z）（？vp,Z/？r）r to calculate Kutta-Joukowski force on particle group in riser is proposed. Furthermore, the local solid holdup and particle velocity profile are studied by PV-6D optical fiber density apparatus via a large-scale cold-model experiment. With the former theoretical method, the radial profile of the Kutta-Joukowski force is proposed on the basis of the experiment results. The influence of solid circulation rate, superficial gas velocity and axial position on Kutta-Joukwski lift force is analyzed. The results show that when dimensionless radius r/R=0, Kutta-Joukwski lift force is 0, r/R is 0.85, Kutta-Joukwski lift force is maximized, Kutta-Joukwski lift force increases with solid circulation rate, the superficial gas velocity has no significant effect on the radial distribution of Kutta-Joukwski lift force, the value in fully developed zone is larger than accelerating zone and export restrained zone. Furthermore, the empirical formulae for the estimation of the radial distribution of Kutta-Joulowski force is set up based on the experimental data and theoretical analysis. The computed and experimental results are in good agreement.