Influence of particle dynamics on erosion test conditions within the centrifugal accelerator type erosion tester

It is well known that particle dynamics behaviour in an erosion tester has a significant influence on test parameters and conditions and, consequently, the erosion test result. This paper examines aspects of particle dynamics in the centrifugal accelerator type erosion tester and their influence on the erosion test conditions, particularly the particle concentration in the particle jet stream and the mass flux on the surface of the eroded target. The effect of particle and particle jet characteristics on particle jet dispersion, particle positional distribution within the jet and particle velocity distribution, and how these in turn effect the mass flux on the target, are examined both theoretically and experimentally. Experimental results showed that a narrow velocity distribution was generally obtained for this type of erosion tester. The velocity distribution was, however, seen to be sensitive to particle characteristics. Experimental measurement of jet dispersion was necessary to allow the mass flux to be estimated. The jet dispersion was determined using a novel technique in which an optical photo-densitometer was utilised to define and measure the diameter of the wear scar on a target. The particle positional distribution was also indicated by this technique. Mass flux was found to vary with position on the target surface and additionally at any given position varied with impact angle. The effect of inter-particulate collisions on mass flux was also considered.