Research on water hammer model and pressure pulsation of digital hydraulic valve control system

It is found through experiments that the amplitude, waveform and periodicity of the water hammer pressure pulsation under the continuous on/off of the valve in the digital hydraulic system are affected by the frequency of the valve switching valve, which is greatly deviated from the prediction and evaluation results of the traditional water hammer model. Therefore, to improve the prediction accuracy of the pressure pulsation (water hammer) model in continuous switching digital hydraulic systems, this work starts from the fundamental water hammer mechanism. Based on the on/off characteristics of the high-speed switching valve, a relationship is established between the valve opening variation and the valve switching frequency through a time-dependent function. Furthermore, by accounting for the elasticity of the pipe walls and the compressibility of the fluid, a novel model capable of predicting water hammer pressure pulsations under continuous valve switching is constructed. The accuracy of this new model was experimentally verified, demonstrating a prediction error for the system’s water hammer pressure that does not exceed 5%. This research model provides theoretical support for the reliability design of high-speed switch valve hydraulic systems by accurately predicting the water hammer pressure of the system under continuous on/off, and is also of great significance for further in-depth research on digital hydraulic valve systems.