Thermodynamic Effect of Tip-Leakage-Vortex Cavitation on 　Two-dimensional Hydrofoils with Tip Clearance for Hot Water

Abstract

Investigation of the thermodynamic effect of tip-leakage-vortex cavitation on a two-dimensional hydrofoil designed with a tip clearance for hot water is reported herein. During unsteady cavitation of water maintained at 90 °C (hereinafter referred to as hot water), the observed decrease in temperature in the tip-leakage region was greater compared to that in the mid-span region. In contrast, during supercavitation of hot water, the situation was reversed (i.e., the temperature decrease in the tip-leakage region was smaller than that in the mid-span region). The cavitation-pattern map for hot water was observed to be largely similar to that for water maintained at 30 °C (hereinafter referred to as tepid water). On the other hand, the amplitude of the dominant frequencies of unsteady cavitation of the hot water was observed to be greater than that of the cavitation of tepid water owing to the sudden collapse of cloud cavitation.