Study On Viscous Oil Flow Characteristics And Performance Optimization Method In Cam Pump Rotor Cavity

With the rapid development of society,the level of science and technology continues to improve,and many emerging industries develop rapidly,the application of the pump is more and more wide,the need for continuous innovation and improvement to adapt to the changing application requirements is expanding,and the cam pump in the pump industry occupies an irreplaceable position.In recent years,the cam pump has been widely concerned by domestic and foreign scholars and enterprises,and achieved remarkable research results.In order to improve the performance of the cam,the cam rotor is no longer limited to traditional straight blade rotor,the rotor several also begins to phyllody more development,major breakthroughs were made in the rotor structure,driving cam pump to the direction of low ripple,low noise,turning situation on which the cam pump is limited because of internal noise vibration problems in a variety of occasions,optimizing of cam pump internal sticky oil flow characteristics,making the cam pump in the delivery of viscous medium to play the greatest advantage.Based on the development trend and key technology of the cam pump,this paper adopts pendulum line and arc-involute-arc rotor profile to complete rotor profile design and 3D modeling.Familiar with the theory and method of numerical simulation,combined with the operation mode of cam pump and the characteristics of Pumplinx software,taking viscous oil as the working medium,the RNG k-εturbulence model is used to simulate the internal flow of the cam pump,and the influencing factors of viscous oil flow characteristics in the cam pump are clarified.According to the deficiency of traditional rotor,the rotor structure is improved,and the influence law of front and back rotor Angle combination and spiral Angle of segmented cam pump and multi-lobe spiral cam pump is analyzed,which provides guidance for selecting matching rotor angle combination and reasonable spiral Angle.Research shows that:(1)In this paper,numerical method is the main,with experimental verification,analysis of the traditional straight blade cam pump by the viscosity of working medium,inlet and outlet pressure difference,rotor speed,found that the three have a great impact on the performance of the cam pump and flow characteristics of viscous oil.With the increase of viscosity,the average flow rate and volume efficiency at the outlet are improved,and the flow pulsation is suppressed,and the fluid velocity distribution in the rotor cavity is more uniform.When the pressure difference increases,the average flow rate and volume efficiency at the outlet decrease,the flow pulsation intensity is basically the same,the radial excitation force on the rotor increases obviously,the maximum absolute value of the force in the x direction increases by 72.85%,and the maximum value of the force in the y direction increases by 80.7%.When the rotational speed increases,the outlet average flow rate,volume efficiency and outlet average pressure increase,but the outlet flow rate and pressure pulsation intensity increase,and the rotor force becomes more and more unstable.The maximum absolute value of radial excitation force F_x component increases by 19.95%,and the maximum absolute value of F_y component increases by 7.42%.(2)In this paper,the piecewise rotor structure and the traditional straight-blade rotor are analyzed from the aspects of rotor outlet flow,total pressure,rotor force,clearance leakage,etc.,the influence of the two rotor structures on performance is studied,and the optimal piecewise rotor angle combination is discussed.The export average flow rate and the export average total pressure of the sectional cam pump is slightly lower than the traditional straight blade cam pump’s,when the traditional straight blade rotor is uesed,flow rate and pressure pulsation is intense,the sectional rotor can reduce the intensity of pulsation.When the initial angle of the rear rotor is-30°and-90°,the pulsation intensity is the weakest.When the initial angle of the rear rotor is-60°,the pulsation intensity is only second to that of the traditional straight blade rotor.The piecewise rotor can reduce the rotor force,and the maximum value of radial excitation force F_x component is 14.40%,9.73%and 14.68%when the piecewise rotor angle combination is(0,-30),(0,-60)and(0,-90),respectively,lower than that of the traditional straight blade rotor.In addition,the segmented rotor structure is beneficial to suppress the leakage of rotor clearance sources.(3)Finally,the spiral rotor can cope with some special occasions on which segmented rotor can’t adapt,this paper on the application of spiral angle to multi-blade rotor research,to reveal the influence of spiral angle on the performance of the cam pump law.The average flow rate and average total pressure at the outlet of the pump are inversely proportional to the spiral angle.The instantaneous flow pulsation at the outlet and the pressure pulsation at the outlet decrease first and then increase.When the spiral angle increases,the gap leakage becomes more and more serious,and the inlet high-speed range gradually decreases,and the overall speed decreases.In addition,the screw angle will affect the force on the rotor.With the increase of the screw angle from 30°to 150°,the pulsation amplitude of the radial excitation force F_x component shows a trend of decreasing first and then increasing.The fluctuation of the radial excitation force F_y component gradually tends to be stable and the amplitude decreases successively,while the radial excitation force F_z component gradually increases.The difference between the maximum and minimum values of force increases from24.039N,25.638N,27.775N,36.436N to 67.843N.In this paper,in order to optimize of the performance of the cam pump as the starting point,combined with the requirements of the diversified development of the cam pump,through the performance of the different rotor structure of the cam pump system analysis,the flow,pressure,speed,rotor force and other performance influencing factors change law is showed,for the promotion and application of the cam pump to provide theoretical guidance.