The numerical simulation of gas-solid flow in fluidized bed has been carried out through double fluid model based on granular dynamics

the influence of different drag force model

restitution coefficient of granular elasticity

and step length of calculated time etc upon mixing and bubbles appeared in the bed being analysed and investigated.Results of numerical calculation show that the different bubble diameter size can be obtained by using different drag force model;by using same drag force model

the fluidization level in the bed may be improved along with increase of the restinution coefficient of granular elasticity;the increase of step length in calculated time can sligbtly decrease the diameter of bubbles in the bed obtained from calculation.