Influence Of Rotor Geometric Parameters On Flow Characteristics Of Rotary Lobe Pump

In recent years,the rotary lobe pump has been widely used in various fields because of its good performance and structural advantages.The rotor is the most important core component of the rotary lobe pump,and the quality of the rotor determines the performance of the rotary lobe pump to a great extent.So,It is very important to study the geometric parameters of rotary lobe pump rotor.The cycloid rotary lobe pump as the research object,using Pumplinx+Scorg combination of rotary lobe pump calculation model of mesh,based on Pumplinx dynamic mesh technology and RNG k-? turbulence model and three-dimensional unsteady numerical simulation of rotary lobe pump,mainly from the Rotor force?the flow characteristics of the pump outlet,the pump chamber the internal flow in three aspects,to reveal the diameter-length ratio of the rotary lobe pump rotor,Spiral angle,influence of blade number on the pump performance,the results of the study show that:(1)The diameter-length ratio of the rotor has a significant effect on the performance of the rotary lobe pump.With the increase of the the diameter-length ratio of the rotor,the average flow rate at the outlet of the rotary lobe pump first increases and then decreases,and the instantaneous flow pulsation amplitude of the pump outlet shows a downward trend,and with the increase of the diameter-length ratio of the rotor,The pulsation amplitude of the transient radial force on the rotor and the mean radial force decreases continuously.With the increase of the diameter-length ratio of the rotor,the flow rate near the rotor increases,and the flow at the outlet of the rotary lobe pump decreases,the flow at the outlet is stable,and the number of vortex increases.The vortex strength first decreases and then increases,and the internal leakage decreases and then increases.overall consideration,When the diameterlength ratio of the rotor is 0.7~1.3,the pump performance is optimal.(2)Compared with the straight blade,the flow rate of the spiral rotary lobe pump decreases and the internal leakage increases,but the pulsation of the outlet flow decreases and the internal flow becomes more stable.With the increase of the spiral angle,the outlet flow rate increases first and then decreases,and the flow pulsation continues to decrease.The vortex and flow separation at the outlet of the pump first decrease and then increase,and only when the spiral angle is 60 °,the pump outlet flow is the largest,the internal leakage is the least,and the hydraulic performance lossis the least,then with the increase of the spiral angle,the vortex and reflux become more serious.With the increase of internal leakage,the performance of the whole rotary lobe pump is reduced,the resultant force of radial force and axial force on the rotary lobe pump rotor decreases first and then increases,and reaches the minimum when the spiral angle is 60°.Considering the influence of rotor spiral angle on the external characteristics and internal flow field of the rotary lobe pump,when the rotor spiral angle is 45°~60°,the flow field loss in the spiral rotary lobe pump can be minimized and the comprehensive hydraulic performance is optimized.(3)With the increase of the number of blades,the outlet flow of the pump decreases and the hydraulic loss increases,but the radial force of the rotor decreases and the flow inside the pump becomes more stable.