Study of Erosion by Solid Particles

The influences of the impacting velocity and the nature of the particles on the erosion of different materials have been studied using a vacuum whirling arm rig. The most important characteristics of natural sand were found to be the size distribution and percentage of quartz present. For artificial abrasives used in industrial processes, erosion can be related to the hardness and sharpness of the particles. Tests on steel and nylon using quartz indicate that there is a fundamental dependence on particle size whereby comparatively little damage is caused by particles up to ˜ 5 μ but larger sizes cause successively more damage till a saturation condition is reached. This dependence is shown to be most important for the design of filter systems for helicopters and other vehicles whose engines suffer through ingestion of dust. Erosion is found to be dependent on a simple power of velocity. For small particles the exponent is 2.0, but for particles bigger than ˜ 100 μ it is 2.3 for a wide range of conditions. The eroding particles are found to incur a substantial degree of fragmentation which is dependent upon the initial sizes and the velocity of impact. It is suggested that the extent of fragmentation of the particles as well as the properties of the target material are important in determining the erosion behaviour.