Experimental study of thermodynamic effect of tip leakage cavitation in hot water

Thermodynamic effect on cavitation appears in cryogenic fluids. The thermodynamic effect is considered to suppress the development of cavitation. The cavitation performance of inducer of liquid rocket turbopump with liquid hydrogen and oxygen is improved by the thermodynamic effect. The authors have conducted experimental studies about thermodynamic effect on cavitation around single hydrofoils in hot water in previous study, where sheet cavity and sheet/cloud cavity occurs. However, cavitation in inducer is not sheet cavity which is separation type but tip leakage cavity which is vortex type. Therefore, in the present study, experiment is conducted about tip leakage cavitation in order to clarify the intensity thermodynamic effect on vortex type cavitation. In the present study, cavitation experiments is conducted with high temperature and high pressure cavitation tunnel, NACA 0009 hydrofoil is chosen for a test body. In the experimental results, development of the pattern of the tip leakage cavitation did not change by the change of freestream temperature from room temperature up to 90 oC. The result of sheet cavitation is in our previous study. The effect of freestream temperature on a temperature reduction inside the cavity is investigated by the direct measurement technique of temperature inside the tip leakage cavity.