| As one of the key components of seawater reverse osmosis engineering, high-pressure pump has important influence on water making cost, operation maintenance and so on. With the advantages of high efficiency, small size, Long service life, high pressure piston pump is suitable for small and medium scale seawater reverse osmosis engineering to reduce energy consumption. However, large work noise caused by flow and pressure pulsation, limits the use of piston pump. The research on flow and pressure pulsation control has a certain gap compared with the overseas. Therefore, investigations on the piston pump flow and pressure pulsation have high theoretical and practical value.Mechanism of piston pump working principle and noise was studied. The movement of piston, leakage between piston and cylinder, leakage between slipper and swash plate and leakage between cylinder and valve plate were analyzed deeply. The interface between piston cavity and valve plate under different rotation angle was analyzed and the formula of flow area was deduced. On this basis, the fluid in the pump is turbulent state, and the standard k-ε was used in the CFD simulation to solve the piston pump model. Then fluid model of the piston pump used in the simulation was established, and the UDF program that controlled the motion of pistons was written. The CFD simulation software Fluent was used in analysis of the model.The influence of number of piston, swash plate angle, rotation speed of cylinder, structure of valve plate and load pressure on the piston pump about the flow and pressure pulsation was analyzed by CFD simulation. It was found that the flow pulsation rate when the number of piston is even is higher than that when the number of piston is odd, and with the increased of piston number, flow pulsation rate gradually decreased. With the angle of swash plate or rotation speed of cylinder increase, displacement piston pump increased, and the outlet flow pulsation rate reduced. When the load pressure increased, the outlet flow pulsation rate of the pump increased. The outlet flow pulsation rate of the piston pump can be reduced more than 60%, when there is damping groove in the transition region of valve plate.Due to the lack of relevant theoretical guidance, this article referred to the analysis method of flow pulsation in the study of piston cavity pressure pulsation. Results shown that, the number of the piston and valve plate damping groove have the same influence on the flow and pressure pulsation. The rotation speed and load pressure of the pump have the opposite effect on the flow and pressure pulsation, and the influence of the swash plate angle on piston cavity pressure pulsation has no obvious regularity. Combining the influence of the above five factors on out flow pulsation and piston cavity pressure pulsation with displacement of piston pump, some reference opinions of piston pump design was given.In the valve plate structure optimization, the angle of width and depth of the damping groove are studied respectively. The results prove that the piston cavity pressure fluctuation and flow pulsation reach minimum when the width angle is about 90°and the depth angle is about 6°. Under the condition of the same flow area, the flow and pressure pulsation of the triangle damping groove is smaller than u-shaped damping groove. |
PDF Full Text Request