Directional Valve Performance And Pressure Pulse Test Bench Design And Research

In order to verify whether the directional valve has enough ability to withstand the pulse pressure within its total life span,this paper studies and designs the pressure pulse test rig.The pressure pulse test bench can generate three kinds of pressure pulse waveforms of water hammer wave,trapezoidal wave and sine wave at the same time,and can adjust the peak pressure,cycle frequency and rise rate of the waveform according to test requirements.The paper first introduces the development background,research significance and main content of the pressure pulse test rig,and describes the composition and working principle of the pressure pulse test rig.According to the function and technical requirements of the test bench,the technical scheme of pressure pulse waveform control was clarified,and the actuators of the hydraulic system were selected.By calculating the thermal balance of the temperature control system,the composition and control principle of the system are given,and the heating and cooling steps are calculated and selected.Based on the deduced mathematical model,a simulation model of the system was established and the feasibility of the closed-loop temperature control system was analyzed.After comparing the pressure regulating performances of the proportional relief valve and the servo proportional valve,two mathematical models of the pressure pulse control system were established respectively.Based on the derived transfer function,two open-loop primary control systems for the pressure pulse control system were plotted.Detu analyzes the stability of the system.On this basis,using AMESim simulation software to analyze the dynamic and static characteristics of the established servo proportional valve model,its characteristic curve is in line with the sample curve.Secondly,according to the two simulation models of pressure pulse control system established,the dynamic response characteristics of pulse waveforms in the two control systems are compared and analyzed.Through the analysis of the error characteristics of the system,it is found that the response time of the proportional relief valve can not meet the test requirements,and thus can not form a standardized pulse waveform.The pressure pulse servo proportional valve control system needs to join the PID correction link to achieve the pulse waveform test index,and find better PID control parameters for different waveforms.Finally,according to the test requirements,the peak pressure,the circulating frequency and the rise rate of the water hammer wave,the trapezoidal wave and the sine wave are adjusted respectively.