Impact Pressure Distributions resulted by an Impinging Jet in Air and Related Erosion

Abstract

In order to establish several techniques of cleaning, deburring and scaling by high-speed water-jets in air, we carefully observe the eroded surface on aluminum-alloy test-pieces in relation to the breakup length of the jet. The impact pressures induced by the impinging jet are also measured by means of pressure-sensitive film. Our experiments are carried out by using the jet test device of 0.5mm in nozzle diameter and 117m/s in jet velocity. The experimental results are as follows : The detected impact pressures were found to be of the order of 130MPa at 117m/s jet velocity. The central concentrated pressure on the impinging surface was observed to be very high locally. Good correlations were found between the impact pressure at the jet axis and maximun erosion depth. The actual erosion pattern on the aluminum specimen was closely related to the distribution of the detected impact pressure in the defused flow region.