The Relationship between Emission Intensity and Erosion Damage Rate for an Orifice Cavitation Flow

Abstract

Cavitation flows emit very weak light and it is closely related to bubble collapses and erosions. In order to obtain the relationship between erosion damage rates and luminescence intensities, erosion tests were performed for a water orifice-cavitation in a pipe flow. In the experiments, a copper plate was set a little downstream from an orifice in the pipe. Damage rates were evaluated by counting the number of damage pits, and luminous intensity was measured in an absolute unit by a photon counter at the wavelength of 450 nm. The number of damage pits was counted by an image processing method and a laser reflection method, too, besides a usual visual inspection method. An empirical formula for the relationship between the erosion and the luminescence intensity was presented.