Numerical Analysis On Performance Of Rotating Blade Vortex Tube Separator

There is a large amount of wind and sand in the northern part of China,and the continuous wind and sand has a great influence on the locomotive diesel engine.When the wind and sand particles enter the engine,some of them will be adhered on the surface of the parts,resulting in a large number of damage to the parts.If not handled in time,excessive sand accumulation will also cause the blockage of the diesel engine pipeline.Therefore,the performance of the intake filter is particularly important to ensure the normal operation of the diesel locomotive.In this paper,a rotating blade vortex tube separator is designed.Based on the theory of gas-solid twophase flow,the flow mechanism inside the vortex tube separator is numerically simulated and analyzed by CFD method.The effects of structural parameters and different working conditions on the flow field and performance of the separator are studied.The main research contents are as follows :A rotating blade vortex tube separator that separates the blade from the tube wall was proposed.Compared with the fixed blade vortex tube separator,the internal pressure,velocity and other flow characteristics of the vortex tube separator with two kinds of blades were analyzed,and the advantages of the rotating blade vortex tube separator in the separation efficiency and pressure loss were explored.The influence of particle size on the separation efficiency was studied,and the physical mechanism of particle movement in the separation process was explored through the particle trajectory and flow field characteristics.The results show that the separation efficiency increases with the increase of particle size,reaching and maintaining at 100 % in a certain range,and then the separation efficiency decreases with the increase of particle size.From the perspective of particle trajectory,due to the small diameter of the rotating blade,there is a gap between the blade and the pipe wall,which makes part of the particles distributed in the outer ring of the vortex tube can directly pass through the gap along the axial direction to the dust discharge tube,while the particles distributed in the vortex tube ring do spiral motion with the airflow after passing through the spiral blade,and the motion law is the same as that of the fixed blade vortex tube separator.The results of the research on the influence of structural parameters on the performance of the separator are as follows : with the increase of blade diameter,the separation efficiency increases first and then decreases,while the pressure loss increases all the time.The increase of blade torsional angle will increase separation efficiency and pressure loss.With the increase of dust discharge gap,the separation efficiency increases and the pressure loss increases.The results of the research on the influence of operating conditions on the performance of the separator are as follows : the increase of the blade speed will increase the separation efficiency first and then decrease,while the total pressure loss increases slightly but the increase is limited.The decrease of scavenging pressure at dust outlet improves the separation efficiency,but also increases the total pressure loss,which affects the efficiency of vortex tube for air treatment.The decrease of outlet back pressure(dust outlet and collector outlet)will increase the velocity of airflow into the vortex tube,improve the separation efficiency of small diameter particles,and decrease the total separation efficiency of large diameter and Rosin-Rammler distribution.