Investigation of cavitation phenomena in the valve port of the high frequency electro-hydraulic digital valve

High frequency electro-hydraulic digital valve (abbr. digital valve) achieves its function by periodical on-offs of the valve ports which formed between the spool shoulders grooves and the sleeve windows, when the spool rotates in the sleeve. Noise and vibration will be induced if cavitation phenomena exist in the valve ports. Severely, the solid materials of valve ports will be subject to cavitation erosion, and the fluid through the valve ports will be discontinuous. As a result, the working characteristics of valve-controlled cylinder will be deteriorated. In this paper, the commercial CFD (Computational Fluid Dynamics) software FLUENT6.3 is used to simulate the flow field inside the digital valve, and reveal the changing rules of the cavitation. Simulation results show cavitation phenomena occur in the lower pressure side in the imminent closure and last a period of time after the closure of the valve ports. However, cavitation phenomena produced in the spool shoulders grooves is different from that in the sleeve windows, such as the speed of cavitation generated, diffusion area and the duration of cavitation. This work provides some useful reference for optimizing the valve structure and reducing cavitation phenomena.