Experimental Study of Cryogenic Cavitation Using Fluoroketone

Cavitation under simulated cryogenic conditions was studied on a NACA0015 hydrofoil in a watertunnel filled with the perfluorinated ketone 2-trifluoromethyl-1,1,1,2,4,4,5,5,5nonafluoro-3-pentanone. Through pressure measurements on the hydrofoil, flash high-speed photography and laser-induced fluorescence in the fluoroketone medium, the extent of cavitation and the characteristic frequencies of its oscillation were studied under varying speeds and angle of attack. While Stc=0.56 oscillations were found for a wide range of conditions, these were attributed to effects of dissolved gas. For properly degassed fluoroketone, Mode I-II cavitation transition was observed to occur in a generally similar manner to in water. The size of the formed bubbles was found to be significantly smaller than in water tests under similar conditions.