Numerical Simulation And Experimental Study On The Gas Solid Flow In The Gate Valve Under Different Concentrations

Gas-solid two-phase flow plays an important role in the rapid industrial development in recent decades and it is an indispensable link in many industrial fields.The valve is one of the most important components in the pneumatic conveying pipeline.As pneumatic conveying system switch,the gate valve may opening and closing frequently during the industrial operation.Due to the throttling effect of the gate,the flow area and flow direction change suddenly.The interaction between gas phase and particle phase changes abruptly under the action of mutation pressure and flow channel coupling.In the process of transportation,the particle phase can even accumulate in the low-flow area of the gate valve cavity.It decreases the running performance and life of the valve.In the serious case,it will make the valve can't work properly,which further affects the whole conveying system.Therefore,this article through the method of numerical simulation and experimental research invest the particle phase flow characteristics and the main surface erosion distribution in the gate valve,provide theoretical support for improving the operation performance of gate valve,optimizing the overall structure of gate valve and improving the durability of gate valve.The main research contents are as follows:(1)Study on erosion induced by dilute gas-solid two phase flow.Aiming at the gate valve erosion of dilute gas-solid two phase flow,the corresponding CFD-DEM numerical simulation method,particle collision bounce model and erosion model were established.And using the SST turbulent model,the effect of valve opening,gas inlet velocity and particle size on the flow characteristics of the particle and the erosion distribution of the main wall of the gate valve in gas-solid two phase flow were researched.And through the corresponding experimental analysis,the accuracy of numerical simulation were verified.The results show that the decreasing of the valve opening,the increasing of the gas inlet velocity and the decreasing of the particle size increase the velocity of particles obtained from the gas and increase the erosion value of the main wall.The maximum erosion value all occurred in the wall near the middle flow channel.(2)Study on erosion induced by local dense gas-solid two phase flow.Aiming at the gate valve erosion of local dense gas-solid two phase flow,a whole of corresponding experimental system were set up.The effect of valve opening,particle size and particle concentration on the accumulation of particles in the channel and erosion distribution of the rear wall of the gate valve were investigated by using the high-speed camera,laser displacement sensor and ultra depth microscope.The results show that with the decreasing of the valve opening and the increasing of the particle concentration,the particles entering the valve cavity increase and the particles gradually accumulate in the cavity.And the different particle size has different effect on the packing effect formed in the cavity.The accumulation of particles near the rear wall of the cavity create a protective effect on the rear wall of the cavity,but the erosion value of the rear cavity wall gradually increase to the maximum at the top after losing the protective effect of the build layer.