Numerical Simulation Of Gas-Solid Two-Phase Flow In The Rotary Coal Powder Separator Based On Fluent

Rotary separator is widely used in thermal power station,it's one of the most important equipment in the coal pulverizing system of power plant.The function of the machine is to make large pulverized coal particles separated and sent them to the mill for regrinding,and fine particles will be sent to the furnace combustion in accordance with the actual conditions of coal demand.The performance of separator has a direct impact on the economy and security of the pulverized coal preparation system.So it is very important to study and analyze the gas and solid two phase flow in the separator.This paper uses CFD-FLUENT software to simulate the gas solid two phase flow numerically.Firstly,numerical simulation of the internal flow field in a rotating separator.The distribution of the flow field is related to the moving state of the particle phase and the separation efficiency of the separator.In order to ensure the accurate flow field distribution,high quality hybrid mesh,high precision RNG ?-? model and two order upwind calculation method with strong convergence are used.In this part,research the distribute situation of gas phase's velocity and pressure,compare the difference between the flow field distribution of the centrifugal separation zone and the non-centrifugal separator zone,meanwhile,analyze the reason why these phenomena will happen.Secondly,numerical simulation of gas solid two phase flow.The DPM model was used to spray the pulverized coal particles,and obtain the trajectory of the pulverized coal particles.And then,explore the effect of the rotor speed on the fineness of pulverized coal and the comprehensive separation efficiency:the fineness of the outlet of the pulverized coal decreases with the increase of the rotational speed,and the comprehensive separation efficiency increases first and then decreases with the increase of the rotational speed,exists a critical speed to make the separation efficiency reach to the highest.Thirdly,change two structural parameters of the impact cone,one is the height of the middle cylinder of the impact cone,another is the taper of impact.Research the the effects of these two parameters on the separation characteristics.The conclusion is that the bigger the height of the middle column of impact cone is,the worse the separation efficiency is,and the bigger the cone taper is,the worse the separation efficiency is.Finally,explore the effect of the number of moving impeller leaves on the separation characteristics.Simulate four groups of rotating separator with different number of leaves,compared these four sets of simulation results,draw a conclusion that with the increase of the number of leaves,the separation efficiency increases.