Euler-Euler modeling of a gas-solid bubbling fluidized bed with kinetic theory of rough particles

摘要

Kinetic theory of granular flow is extended for rough particles. Both the translational and rotational granular temperatures are introduced to characterize the random fluctuations of particles. Sliding and sticking mechanisms are distinguished in the binary collision model with the friction coefficient and coefficients of normal and tangential restitution. Collision integrals are performed to produce new expressions of the constitutive relations for rough particles. Flat wall boundary conditions for rough particles are proposed according to the particle-wall collisions. The present model is incorporated in Euler-Euler simulations of a bubbling gas-solid fluidized bed. The computed bed expansion dynamics and flow patterns are validated with experimental measurements and Euler-Lagrange simulations. The ratio of rotational to translational granular temperatures is found to be influenced by the particle volume fraction and the fluidization velocity. Comparison among the present model, the original smooth particle model and another rough particle model is also carried out.