Effect Of Local Erosion On The Separation Performance Of The Cyclone Separator

Cyclones are multiphase flow separation devices that rely on centrifugal force from the rotation of dusty gases to separate particles,and are essential purification equipment for many industrial processes.However,when used for separation of super-hard solid particles,wall perforation failure due to wall erosion and wear could cause significant safety hazards and economic losses.Therefore,the study of the wall erosion characteristics of cyclone separators and its influence mechanism on the separation performance of the equipment can provide a basis for the safe and stable operation of cyclone separators,which has very important theoretical value and practical significance.In this work,the Reynolds stress model（RSM）,the particle random particle model（DPM）and the Oka erosion equation were applied to explore the erosion characteristics of the cyclone gas-solid two-phase flow and the mechanism of erosion on the flow field and performance of the equipment under the Euler-Lagrange numerical calculation method.The research methods and results of this work are as follows:Analysis of the erosion characteristics of the cyclone separator,and found that the overall erosion of the equipment wall spiral belt distribution,and serious erosion parts are mainly concentrated in the top of the cylinder,the inlet facing the cylinder wall and the bottom of the cone near the dust discharge port.When the inlet velocity is constant,the impact angle between the particles and the wall is about the same,and the serious erosion parts are concentrated at the wall facing the cylinder inlet,the top of the cylinder and the bottom of the cone near the dust discharge port,and the erosion rate increases with the increase of the particle concentration and particle size.1.23×10^-4 kg/m²·s.Through the cyclone erosion deformation analysis,the cyclone erosion deformation model was proposed,and the particle image velocimetry（PIV）system was used to experimentally study the flow field of the cyclone with erosion deformation.The erosion of the equipment wall causes an obvious short-circuit flow and local vortex flow inside the cylinder,and the angle between the trajectory of the particles in the cone and the equipment axis increases from nearly 45°when it is not worn to 60°,and the closer the wear position is,the closer the trajectory of the particles is to horizontal rotation.The erosion of the cyclone separator led to a decrease in separation performance,with a local erosion thickness ofδ=15 mm,the maximum tangential velocity decreased by about 17.5%and the minimum tangential velocity shifted to the side of the radial position by an average of 23%;for particles of 4μm particle size the separation efficiency decreased from 100%to 93%without wall erosion,the cut particle size d50increased from 1.3μm to 1.9μm,and the equipment pressure drop decreased by about46.7%.The study of the effect of cone erosion spiral angle on the flow field and performance of cyclone separators showed that the erosion spiral angle has less effect on the tangential velocity and axial velocity magnitude,and leads to the reduction of the quasi-free vortex separation region in the separation space which weakening of the stagnation at the quasi-forced vortex nucleus,and the stability of the quasi-forced vortex region.In addition,compared with the unwearable cyclone（α=0°）,the erosion spiral angleα=30°,the device could completely separate the particle size from 4μm when the cyclone wall is not worn to 8μm,and the separation efficiency of the device for 3μm particles decreases from 99%to 81%.Through the study of the effect of cone erosion thickness on the flow field and performance of the cyclone,and found that the erosion of the bottom of the cone led to the expansion of the area affected by the longitudinal eccentric vortex inside the cone,which intensified the influence of the precession vortex core（PVC）on the flow field,resulting in the reduction of the tangential velocity and the increase of the axial velocity of the cyclone,and the reduction of the centrifugal force on the particles.Compared with the cyclone without erosion,the tangential velocity of the cyclone decreased by about27%and the centripetal acceleration increased by about 11%when the cone local erosion thicknessδis 20 mm,the cyclone separation efficiency decreased from 100%to 93%for particles with 4μm particle size,the particle cut size d₅₀ increased from 1.3 to 1.9μm,and the cyclone pressure drop decreased by about 40%.