Focusing on geometrical effects of nozzle outlets and jet-impinging surfaces, the experiment on cavitation erosion was conducted. Three types of nozzle holders and three different height of cylindrical walls or thickness of spacers were prepared; for nine combination the geometrical conditions around the submerged cavitating jet were examined. Tap water was used as the test liquid and the temperature was kept at 40-C. The upstream pressure was specified at 10.1 MPa and the downstream was at 0.2 MPa. The specimens of 15 mm in diameter were made of aluminum alloy. The time evolution of mass loss and cross-sectional profiles of the specimens were measured every 15 min, 30 min or 1 hour. The erosion rates were calculated and the maximum rates were compared. The erosion was minimized at the condition of combination of the nozzle outlets and the specimen surfaces which caused less erosion.
