CFD Simulations of Complex Fluid Flow in Gas-Solid Fluidized Bed Using Modified k-ε Turbulence Models

摘要

This work studies the effect of kinetic Prandtl value in the k-ε turbulence model transport equation on the characteristics of fluidized bed fluid flow. The research was conducted using CFD simulation method. Three kinetic Prandtl values were chosen, namely 0.8; 0.9 and 1.1; plus 1 from the default value of the turbulent model. The parameters observed were the difference in pressure in the bed, and several turbulence parameters, i.e. the rate of dissipation, the effective viscosity of the gas and the particles. The turbulent model with k-Prandtl of 0.9 gives the most accurate results at the superficial velocity range of 0.40 m/s - 0.70 m/s, while k-Prandtl of 1.1 gives most accurate results at the superficial velocity range of 0.80 m/s - 0.90 m/s. It is found that the decrease in the k-Prandtl value causes the decrease in the dissipation rate; same phenomena with effective viscosity of gas. Meanwhile, there is no significant change in the particle's effective viscosity with the change of k-Prandtl value.