Cavitation Characteristics Of Aviation Poppet Pressure Valve And Its Influence On Spool Vibration

The poppet pressure valve is widely used in the aviation hydraulic system.It has a large inlet and outlet pressure difference,and a fast flow rate with a strong shear flow.Due to this,cavitation is easy to occur in the poppet valve flow field,leading to erosion and valve spool vibration,which reduces product stability and service life.To solve this problem,the cavitation characteristics and its influence on spool vibration are studied based on a typical poppet pressure valve structure in the aviation field.This paper focuses on the following study work:(1)Cavitation mathematical model on the poppet pressure valve.Based on an aviation poppet pressure valve structure,the working principle is analyzed and the flow field area is determined.The detached eddy simulation method is used to simulate the flow field considering cavitation.The influencing factors of cavitation initiation are revealed,and the quantitative evaluation parameters and analysis methods of cavitation are proposed.(2)Cavitation evolution mechanism of the poppet pressure valve.Based on the flow field simulation method,the typical flow field structure and cavitation area of the pressure poppet valve are analyzed.A typical cavitation period is selected to analyze the unsteady space-time evolution mechanism of cavitation from the dimensions of body cavitation and surface cavitation,vortex recognition and gas volume fraction isosurface methods are used to investigate the distribution of main vortex structures in the flow field and their effects on cavitation.(3)Cavitation periodicity and spool vibration of the poppet pressure valve.Based on time-domain and frequency-domain analysis methods,the cavitation periodic flow rule of the poppet pressure valve is revealed from the dimension of volume,surface and point.The effects of pressure difference and back pressure on cavitation characteristics are compared and verified,and the influence of cavitation on valve output flow,pressure pulsation and flow force on the valve spool surface is analyzed.The natural frequency of the valve spool is calculated and the influence of cavitation on valve spool vibration is simulated.(4)Cavitation visualization experiment of the poppet pressure valve.Based on the principle of grayscale recognition,a visual experiment platform is built for the poppet valve to observe its characteristic plane cavitation structure distribution.The grayscale time-average method is used to process the image,and the velocity impact on the plane cavitation characteristics is compared and analyzed.The theoretical analysis and simulation results is verified by experiments.This paper will have a guide for clarifying the periodic evolution of cavitation in the aviation poppet pressure valve and its influence on the spool vibration characteristics,and provides a research basis for the poppet pressure valve to restrain cavitation and improve its stability.