Numerical Simulation Of Strong Turbulent Flow Field And Structual Optimization Of Cyclone Separator

This paper presents a numerical study on the gas flow and the gas-solid flow in the circumfluent cyclone separators using the computational fluid dynamics commercial software FLUNET, analysis the flow field in the cyclone, the moving trace of particles and the factors which influence the pressure drop and the collection efficiency. The effects of outer chamber heights and annular gap size on the dimensional flow field and separation performance in the cyclone were also studied, the research result will provide further reference for a optimization design of the circumfluent cyclone and offer scientific theory basis for solving the separation problem of submicron dust. The main research works are as following:(1) The Reynolds stress turbulence model (RSM) was selected to simulate the circumfluent cyclone separators. Excellent convergent results were obtained by reasonable analyzing and debugging, based on this, the velocity field, the pressure field and the turbulent flow field were researched. The results show that:The tangential velocity has well symmetrical, The maximum tangential velocity is at the wall of the inner cylinder, while at the center of the cylinder is comparatively small; at the above of the CFC inlet, the axial velocity which at the first separator zone is upward; the dynamic pressure, static pressure and total pressure has well symmetrical, the static pressure and total pressure increases along radial direction from center to cyclone wall, The lowest value is at the center of vortex, the gradient in axial direction is very limited; The maximum turbulent kinetic energy was all found at the cone which connect with the cylinder.(2) On the basis of gas flow, the moving trace of particles was studied by using interphase coupling stochastic trajectory model and the simulated result of the collection efficiency with different particle diameter are compared with the experimental data. The results show that:the movement of particles is very complex and has great randomness; When the particle diameter is small, the collection efficiency is increased as the particle size increases; When the particle diameter is bigger, the collection efficiency decreased first and then increased as the particle size increases; The numerical simulation results are in good agreement with the experimental data at different particle diameter. It is possible to say that the numerical simulation results have certain predictability.(3) Under the same operating parameters, the effect of outer chamber heights and annular gap size on the pressure drop and the collection efficiency of the cyclone were discussed. The results show that:increasing the outer chamber heights and reducing the annular gap size properly can increase collection efficiency and decrease pressure drop which provides a strong theoretical basis for the optimization design of the circumfluent cyclone.