An investigation of particle dynamics within a centrifugal accelerator type erosion tester

Abstract

Particle impact erosion is usually tested experimentally using one of two major types of erosion testing device; the gas-blast tester and the centrifugal accelerator type tester. The influence of the choice of the tester on the erosion results obtained has been recognised, together with the need for a better understanding of particle dynamics within the testers to allow correct interpretation of the erosion test results. To date, relatively little work has been carried out on understanding particle dynamics in the centrifugal tester, and this paper attempts to redress this. The paper considers the dynamics of particles travelling down the acceleration tube in the tester. A comprehensive physical model is described taking account of airflow in the acceleration tubes, particle rotation and friction effects. This led to the development of a computational model to predict the particle velocity vector (particle velocity and exit angle). The predictive model indicates the important influence of particle shape on particle dynamics and suggests that particle size has little effect. This implies a sensitivity of particle velocity and exit angle to the coefficient of friction of the particle in the acceleration tubes. Experimental measurements were carried out and the results verified the predictions of the model.