A Mathematical Model And Subsequent Verification Of The Influences Of Viscous Force And Resistant Force On Granular Materials Flow In Packed Bed

The moving bed is widely used in iron and steel industry,petrochemical industry,energy and environmental protection.The viscous medium theory is one of the research directions of granular materials flow in moving bed.The viscous continuum thory of granular materials could not predict the flow and dead zone.This study attempts to establish a dynamic model for predicting the flow field and dead zone in the whole bed,and it changes the present situation of the velocity field in the flow field by using the continuous medium equation.Particle flow experiments are carried out to verify the reliability of the model.Based on the experimental results and predicted results,the influence of viscous force and resistance on material flow is analyzed.The main results are as follows:(1)Based on the analysis of the dependence of dead zone and flow are,the expression of material flow resistance is obtained.It is shown that the larger the apparent velocity is,the better the material circulation is,and the stronger the particle material is to maintain its motion state by inertia.(2)Considering resistant force and viscous force of materials flow,a mathematical model is established to predict dead zone and the distribution of velocity by considering conservation principle.(3)The reliability of the model is verified by experimental results and the values of experimental model parameters are obtained: the viscosity coefficient of millet is 0.04g·cm-1·s-1;the kinetic parameters A and B are 10.11g-1·s·cm3 and 13.2-1·s2·cm2,respectively.(4)The flow area of central discharge is not obvious with the discharge velocity.The effect of viscous force acting on the surface of the control body on the flow field is not the dominant factor.The viscous force is the main factor to form the near wall area of eccentric discharge.When the viscosity is zero,the maximum flow velocity in the flow area of the eccentric discharge is on the side wall.With the increase of the viscous force,the maximum flow velocity moves in the flow region horizontally.(5)The main factor affecting the materials flow area is the resistance in the control body.With the increase of the kinetic parameter A,the flow coefficient increases,the flow resistance decreases,and the material flow area becomes smaller.With the increase of the kinetic parameter B,the change of the circulation coefficient with the speed is stronger,and the flow area is not obvious with the discharge rate.The model could predict the dead zone and the distribution of granular material velocities in flowing zone.To provide a way to solve the problem that the dead zone and the flow area can not be predicted in the simulation of the continuous medium,and it provides support for the relevant theoretical research.