Theoretical Research And Simulation Analysis Of Air Leakage In Pneumatic Conveyor Rotating Valve

Pneumatic conveying rotary valve,as one of the most commonly used continuous feeders in the pneumatic conveying system,can continuously and evenly convey the materials in the system to the next link,and has the function of airtight lock,widely used in chemical,food,materials and other industries.China’s pneumatic conveying industry started late,the research on rotary valve is more rare,the theoretical basis is weak,for the existence of the air leakage of rotary valve,usually by referring to foreign relevant products or engineering experience to determine,limiting the further development of China’s pneumatic conveying industry.The working conditions and structural parameters of the rotary valve have a significant impact on the leakage of the rotary valve.Based on the rotary valve with a diameter of 130 mm and an axial length of 148 mm,the working pressure difference of0.15 MPa,this thesis uses numerical simulation technology to study the pneumatic conveying rotary valve.The main research contents are as follows:(1)The theoretical calculation of air leakage of pneumatic conveying rotary valve is carried out,and the mathematical model of air leakage of pneumatic conveying rotary valve is obtained by replacing the changing number of blades in contact with the inner wall of the rotating valve body with the average number of blades.(2)The three-dimensional fluid domain simulation model of pneumatic conveying rotary valve was established,and the steady-state calculation of the leakage of rotary valve was carried out by the method of computational fluid dynamics(CFD).Based on Fluent software,the leakage volume of 5 groups of rotating valves with different axial sizes,9 groups of fixed volumes with different aspect ratios,and 5 groups of different blade thicknesses were simulated and analyzed.(3)Based on the steady-state simulation results of pneumatic conveying rotary valve,given the rotating valve speed of 18 rpm,the transient calculation was carried out for 5 groups of different axial sizes,9 groups of different length to diameter ratios of fixed volumes and 5 groups of different blade thicknesses,and the change of leakage amount of pneumatic conveying rotary valve under different rotor speeds was studied.Based on the steady-state simulation calculation and transient simulation calculation in Fluent fluid simulation software,the leakage of pneumatic conveying rotary valve is studied,mainly including the length-to-diameter ratio of rotary valve,blade thickness,rotor speed and other parameters are analyzed,which plays an important guiding role in the production,design and selection of rotary valve.