Experimental study of appearance of thermodynamic effect on cavitation in hot water

Abstract

In this study, in order to clarify a relation between thermodynamic effect, which suppresses cavitation, and scale effect, which promotes cavitation, tunnel experiment was done with NACA16012 single hydrofoil in hot water. Appearance of the effects was estimated by occurrence region of cavitation for angle of attack vs cavitation number and variation of cavitation patterns. Main flow temperature was 30°C and 70°C. By increasing main flow temperature under constant Reynolds number condition, scale effect was took away to some extent and thermodynamic effect was picked out. From the result, occurrence resin of cavitation was suppressed in 70°C hot water, where it is empirically known that thermodynamic effect does not appear in such a low temperature. The result indicates that thermodynamic effect and scale effect, which are conflicting effects, cancelled each other in water at 70°C. Additionally it was shown that occurrence of cavitation was drastically suppressed in a condition of specific angle of attack.