Study On Optimization Of Anti-cavitation Structure Of Hydraulic Poppet Valve

Hydraulic poppet valve is one of the commonly used hydraulic components in hydraulic system,but because it is prone to cavitation,resulting in unstable system pressure and flow,and also causes cavitation damage to components,which seriously limits the scope of application of the poppet valve.In order to reduce the occurrence of cavitation of the poppet valve,this topic will study the optimization design of the anti-cavitation structure of the hydraulic poppet valve.Aiming at the cavitation problem of water hydraulic cone valve,this paper uses Fluent software to analyze the cavitation flow of the full cone valve,and puts forward the improvement scheme of the anti-cavitation structure of the cone valve.The Kriging agent model is used to optimize the design,and the ideal anti-cavitation cone valve structure is obtained.The specific research is as follows:(1)The cavitation flow analysis of poppet valves,and discuss the influence of the change of cone angle and opening of valve spool on cavitation.The turbulence model,the mixture model and the cavitation model in Fluent software are used to simulate the poppet valve by CFD.The pressure distribution,velocity change and vapor volume fraction of the flow field in the valve are analyzed.It is found that the high velocity and low pressure at the valve port are the main areas of cavitation initiation.Then,through the simulation analysis of the poppet valve cavitation under different core cone angle and different valve opening,the influence of the change of core cone angle and valve opening on the poppet valve cavitation was studied.(2)The poppet valve structure improvement.In order to restrain the occurrence of poppet valve cavitation,the structure of poppet valve mouth was improved.The improved model a is to open a triangular groove on the chamfering surface of the poppet valve seat.The model b has a triangular groove in the cone of the valve core.The cone surface of model c is changed into two conical surfaces with different cone angles,and a certain distance between the cone surfaces is set aside.Compared with the cavitation simulation of three models,the anti-cavitation effect of model c is the best.(3)The structure of the improved poppet valve model c is more complex.Through the analysis,it is found that the cone top half-cone angle P,the bottom half-cone angle Q and the distance H of the cone face of the poppet valve are the three main parameters affecting the poppet valve cavitation.Five-level full-factor experimental designs are carried out for these three parameters and 125 models are obtained.Cavitation analysis of each model are carried out to obtain the vapor volume fraction of the poppet valve,which is prepared for the establishment of Kriging agent model.(4)The Kriging agent model of the top half-cone angle P,bottom half-cone angle Q and the distance H between the cone surfaces and the average vapor volume fraction of the poppet valve are established.Then the accuracy of the model is verified.The genetic algorithm is used to optimize the surrogate model to obtain the optimal structural parameters of the poppet valve to suppress cavitation.This research provides a theoretical basis for the study of the cavitation flow and the design of the anti-cavitation structure of the hydraulic poppet valve.So it has a certain reference value.