Research On The Gap Sealing Characteristics Of High Pressure And Large Flow Water Medium

High pressure seal is one of the key control factors of various high pressure plunger pumps,and it is also a key component to ensure its reliable operation.Traditional crank connecting rod type high pressure radial plunger pump often use packing seals,which have the disadvantages of high friction,low efficiency,and short life.Therefore,a non-contact gap seal is designed in this paper,and green clean pure water is used as the working medium.The theoretical research and simulation experiments of the sealing mechanism of the hydraulic annular clearance seal are carried out.The research methods and results provide theoretical basis and guidance for designing the gap seal of reciprocating high-pressure large-flow water hydraulic plunger pump.First,based on the basic theory of the hydraulic annular gap flow,the theoretical analysis of the leakage of the hydraulic annular gap seal is carried out.At the same time,considering the movement speed and eccentricity and inclination state of the plunger assembly,the viscous effect and inertia effect and viscous pressure effect and compressibility of the water medium.Finally,considering the dynamic change of the seal length,the theoretical calculation formula of leakage amount is obtained.This theoretical calculation formula is compared with the rest of the theoretical calculation models that have been proposed,thus the change law of leakage volume and volume efficiency is obtained.Subsequently,a three-dimensional simulation model of the high-pressure largeflow gap seal is established.The flow field simulation is performed through FLUENT,and the leakage and volumetric efficiency of water hydraulic annular gap are analyzed when the water medium is in both compressible and incompressible states at different inlet pressures.By calculating the compression leakage flow rate,the law of the proportion of compression leakage with changes in pressure after taking into account the compressibility of water is obtained,and the influence law of medium compressibility on the leakage and volumetric efficiency of high-pressure large-flow gap seals is revealed.Finally,the comprehensive deformation of the plunger pair is simulated through the joint simulation of ANSYS Workbench and FLUENT.The radial pressure deformation,axial pressure deformation,thermal deformation and thermo-pressure coupling deformation of the plunger and the plunger sleeve are analyzed,and their respective amount of deformation are obtained.Then,the variation of the leakage and volumetric efficiency of the plunger pair with the changes of the pressure and temperature is analyzed by the amount of deformation.