Experimental Study on Water Hammer Pressure Pulsation in Digital Hydraulics

Water hammer pressure pulsation is caused by the switching characteristics of digital hydraulics, resulting in a decline in digital hydraulic performance, which is also a research difficulty of digital hydraulics. However, the current classical water hammer theory cannot accurately describe the water hammer pressure pulsation in the digital hydraulic system. Therefore, the water hammer pressure pulsation of digital hydraulic system is described by experimental method. Three phenomena were found by using the designed water hammer pressure pulsation test bench: (1) In the process of propagation, the waveform of water hammer pressure fluctuation has three kinds of changes with the increase of driving frequency. (2) When the switching frequency of the high-speed on-off valve is not less than 130 Hz, the stability time of the water hammer pressure pulsation is proportional to the switching frequency. (3) After the water hammer pressure fluctuation is stable, the water hammer pressure fluctuation will increase first and then decrease with the increase of frequency.