Study On The Law Of Particle Movement In Cyclone Separator Under Coriolis Force

As a simple,convenient and reliable gas-solid separation equipment,cyclone separator is widely used in chemical,petroleum,energy,environmental protection,mining and many other fields.At present,the problems of energy shortage and the increasingly serious environmental protection,more strict requirements about design and application of the cyclone separator are put forward.However,due to the inside of the cyclone is anisotropic three-dimensional strong cyclone flow field under the effect of the Coriolis,the movement of particles in which is extremely complex.Therefore,it is very important to study the structure of the internal flow field and the motion of the particles in the cyclone separator,which is of great significance to the structure optimization and performance improvement of the cyclone separator.In this paper,the gas flow field and the gas-solid two-phase flow field of the straight-cut cyclone are studied by means of experimental and numerical simulation.The details are as follows:(1)The pressure difference between inlet and outlet of cyclone separator and the separation efficiency of particles were measured by experiment.(2)The inlet and outlet pressure difference of the cyclone is calculated by using different turbulence model and compared with the experimental data.The results show that the Reynolds Stress Model(RSM),the QUICK format of the convective term and the PRESTO pressure interpolation scheme of the pressure gradient term are more suitable for the simulation of the flow field of the cyclone.By analyzing the gas flow field,the tangential velocity and the axial velocity play a leading role in the separation of the particles.The pressure drop is dissipated in the form of energy,and the energy dissipation in the exhaust p ipe is the most serious.The presence of the main stream mixed with some secondary flow will change the flow field structure,thus affecting the separation of particles.(3)On the basis of the gas flow field,the gas-solid two-phase flow field of the cyclone separator is numerically simulated by using the Discrete Phase Model(DPM)and the Discrete Random Walk(DRW)based on the random orbit model.The results show that the discrete phase model has a certain accuracy in the simulation of gas-solid two-phase flow field by comparing the experimental results,the theoretical and numerical results.(4)By studying the relationship between trajectory and particle size and inlet position,it can be seen that the fine particles are greatly affected by the short air flow due to the large effect of air sticking.The small particles are affected by the longitudinal vortex flow,so it appears the alternating movement between the internal and external cyclone.Large particles are mainly affected by the eccentric circulation in the bottom of the cone.In addition,for the fine particles,the separation efficiency is the highest when the particles enter from the lower part of the external of the inlet.For the small particles,the separation efficiency is the highest when the particles enter from the lower part of the inlet.And for the fine particles,the separation efficiency is the highest when the large particles enter from the upper and the outer area of the inlet.(5)According to the results of the study of particle motion,the intake pipe of the cyclone is changed to the undulating structure.Through the simulation study,it is found that when the necking angle is 20°,it can not only effectively improve the separation efficiency of the cyclone separator but also could not lead to the excessive energy loss caused by the rapidly increased pressure drop of the separator.