Design And Research On Erosion Reduction Structure Of Cyclone Separator

The cyclone separator is widely used in the industry,but the internal flow field of the cyclone is very complex.In addition,the wall of the cyclone separator is subject to serious erosion,which is one of the main reasons leading to the unplanned shutdown of the cyclone separator,as well as significantly reducing their service life.Therefore,it is necessary to design the structure of the cyclone for erosion reduction.Based on the Lapple cyclone separator,two types of anti-erosion cyclone separators,the extra inlet cyclone and necking inlet cyclone,were designed in this thesis.Comparative analysis of the flow field and erosion characteristics of the cyclone separator by the method of numerical simulation and experiment.The main contents of this thesis are as follows:(1)The numerical simulation method of the cyclone separator was investigated.The Reynolds Stress Model was used to calculate the gas phase,the Discrete Phase Model to calculate the particle trajectory and the Finnie model to calculate the erosion.At the same time,the structured grid of the cyclone separator is divided by ICEM and the grid-independence is verified.Finally,the correctness of the numerical simulation method is verified by experiments.(2)The four parameters(extra inlet width,extra inlet angle,extra inlet number and extra inlet velocity)of the extra inlet cyclone separator were optimized by single-factor experiment and response surface design.The single-factor experiment shows that the extra inlet width,extra inlet angle and extra inlet velocity have a significant effect on the pressure drop,while the four parameters of the extra inlet cyclone have little effect on the separation efficiency.According to the variance analysis,response surface analysis and optimization of the second-order response surface model,the optimal combination of the extra inlet width of 4.5 mm,the angle of the extra inlet angle of 23 ° and the velocity of the extra inlet is 12 m/s.In addition,it can be found from the velocity vector diagram of the cyclone separator that the extra inlet cyclone has obvious axial downward airflow under the roof,which will inhibit the formation of the top ash ring and significantly reduces the erosion of the wall.At the same time,the air flow in the vortex finder with the extra inlet cyclone does not rotate,and the static pressure in the vortex finder is obviously restored,which will reduce energy loss and pressure drop.(3)The effect of the necking inlet structure on the wall erosion was analyzed.when the inlet necking height was 0.05 D and 0.10 D,there is no top ash ring formed in the cyclone,so the erosion in the annular space is smaller and the separation efficiency is higher.However,the erosion of the Lapple cyclone in the cylinder and cone is smaller than that of the necking inlet cyclone.At the same time,The necking inlet structure results in a gradual reduction of the inlet cross section,which has a certain acceleration effect on the airflow.Thus,the tangential velocity of the necking inlet cyclone increases,which benefits the particle separation,but the pressure drop also increases.Considering the performance and erosion of the inlet necking cyclone,inlet necking heights of 0.05 D and 0.10 D are considered preferable.