Simulation Research On Working Performance Of The Rotating-sleeve Distributing-flow System

Compared with the one-way valve and the electromagnetic reversing valve,the rotating-sleeve distributing-flow system for reciprocating plunger pump has a compact structure and low pressure loss,especially in high frequency and large flow situations.Previous researches have involved kinematics and dynamics,and have obtained preliminary design plans and analysis results.However,important characteristics such as cavitation,working pulsation,and efficiency have not yet been addressed.In view of the above problems,considering the working conditions of the distribution system,the theoretical analysis and simulation of the system have been completed,and the characteristics of the rotating-sleeve distributing-flow system have been thoroughly and comprehensively analyzed to provide the basis for structural improvement and optimization.According to the rated working conditions of the distribution system(speed 1200r/min,load pressure 2Mpa)and application occasions,the virtual prototype of the distribution system was designed,including the inner diameter of the inlet and outlet,spherical pin design,spring and so on.At the same time,the mathematics model and physical model of the distribution system are established.Through the joint simulation of FLUENT and MATLAB,the cavitation phenomenon and turbulent kinetic energy distribution in the whole flow field were simulated.The cavitation phenomenon mainly occurs in the early stage of the inflow phase and concentrates in the pump chamber and the distribution port.The distribution of turbulent kinetic energy is closely related to the flow direction and flow velocity.Three kinds of flow-distribution port structures were proposed and three kinds of flow-distribution port allocation areas were established using MATLAB.The results showed that the square-distribution flow-distribution port had the largest flow area,followed by the circular flow-distribution port,and the smallest area was the double-flow-distribution port.And the results of flow characteristics analysis showed that the outlet flow rate of the square flow distribution outlet was the most stable,and the pressure fluctuation of the double distribution outlet was the most stable.Therefore,considering the distribution area and the pulsation,the square flow distribution port is most suitable for system work.Two types of damping trough structures are designed,and the flow distribution areas are basically the same.The flow field of the damping trough is turbulent in different operating conditions,and the Utype damping trough ratio is analyzed from the aspects of flow pulsation,pressure pulsation,and velocity vector distribution.The performance parameters of the triangular vibration damping trough are more stable.According to the angle distribution of the pressure transient process and the closed system during the flow distribution process of the distribution system,the mathematical model of the pressure change inside the pump chamber is deduced,and the optimal closed dead compression 4°and closed expansion angle 1° were selected by the fluid simulation.The outlet flow,flow amplitude,and flow pulsation were simulated at different speeds and pressures.The results showed that the volumetric efficiency was 97.9% under rated conditions.The volumetric efficiency increases first and then decreases with increasing speed.The maximum efficiency is 98.3%,and the minimum efficiency is 56.8%.At the same time,the volumetric efficiency continues to decrease as the load pressure increases.The maximum volumetric efficiency is 97.9% and the minimum efficiency is 82.6%.