Study On Transient Cavitation Flow Of Spool Valve With V-grooves

The complex hydraulic throttle valve with V grooves have been simplified.In fluent,the transient cavitation numerical simulation of throttle valve with V grooves was carried out by using the viscosity-corrected RNG k-? turbulence model,the retractable wall function,the Z-wart cavitation model and dynamic mesh technique.The primary cause of the bubble growth and collapse at different conditions is explored by numerical simulation.The influence of the amplitude and frequency of the inlet pressure on the cavitation of the valve is studied by the UDF subprogram to control the sinusoidal variation of the inlet pressure.The main works and results are as follows:1.The research meaning of this subject is are briefly outlined.The development history of cavitation phenomenon is introduced.The research situation of cavitation in hydraulic valves both domestic and overseas and the application of high-speed photography in the visualization of flow field are emphatically introduced.Meanwhile,the main research direction and content of this thesis are summarized.2.The RNG k-? turbulence model and its viscosity correction method are briefly summarized,and the density before and after correction is compared.The basic theory of bubble growth and collapse near solid wall.3.The throttle valve with V grooves is simplified and transient cavitation is carried out to simulate the simplified model.At certain valve opening,the phenomenon of bubble growth and collapse under different flow direction and valve pressure difference is studied.And the reason of attached cavity falling off is explained.As the sinusoidal variation of the inlet pressure varies with time,the effect of pressure pulsation amplitude and frequency on the cavitation intensity of the valve is investigated.At the same time,dynamic mesh technology is used to study the change of cavities in valve opening and closing.4.According to the simplified throttle valve with V grooves,the corresponding experimental model is designed and the complete experimental system is set up.The images of the spiral type ascending motion and deformation of single bubble,as well as multiple bubbles merging with each other are shot by the high-speed camera at primary stage.The surface morphology of the key position for the experimental model is observed and marked by using the 3D surface profilometer.