Numerical Prediction of Hydrodynamic Characteristics of Wet Particles and Power-Law Fluids in a Fluidized Bed Using the Dynamic Restitution Coefficient

Abstract

The hydrodynamic characteristics of the non-Newtonian fluid and wet particles are studied by a kinetic theory-based two-fluid approach. The dynamic restitution coefficient for wet particles is applied to calculate the instantaneous restitution coefficient, which is a function of the Stokes number calculated based on the local strain rate. Furthermore, the dynamic critical Stokes number is utilized to judge whether particles rebound after a collision. In addition, a modified drag model is applied to study interphase interactions. The effects of both the interstitial fluid on the wet particle collision and particle concentration on the rheological properties of the non-Newtonian fluid are considered. The results show that the interstitial liquid viscosity between colliding particles is less than the liquid-phase viscosity. The critical Stokes number decreases with the increase of rheological parameters. The predicted critical Stokes number in non-Newtonian fluids is between 7 and 8, which is in agreement with the experimental results.