Development of Oil Hydraulic Components Using a Flow Visualization Technique

In the present study, we succeed in observing cavitating flow near a notch (V-shaped groove) in a valve plate in an axial piston pump, and we improve an oil hydraulic ball valve, using the visualization technique. Our model of the axial piston pump, is designed to allow the jet flow near the notch and the cavitation cloud to be observed clearly from two directions using a high-speed video camera. Computational Fluid Dynamics (CFD) is employed to estimate the occurrence and the region of the cavitation cloud. It is found that our CFD method is very useful for estimating the region of the cavitation cloud. It is further found that adding notches serves to greatly reduce the cavitation region. Using a commercially available digital video camera, a high-speed video camera, and X-rays source, we also succeed in improving an oil hydraulic ball valve by preventing vibration, cavitation, and the noise.