Towards prediction of flux effects in powder blasting nozzles

The efficiency of solid-particle erosion generally decreases with increasing particle flux. The particles rebounding from the surface collide with incoming particles, which results in a decrease in their velocity and the inflicted damage. This effect, called 'the flux effect', was modelled by Anand et al. [K. Anand, S.K. Hovis, H. Conrad, R.O. Scattergood, Flux effects in solid particle erosion, Wear, Vol. 118, 1987, pp. 243-257.] with a single-parameter fit model. Although this fit parameter was assumed to be constant, experiments have yielded a wide range of values for it, making the model unsuitable for flux-effect predictions. This paper shows for one erosion process-glass by alumina particles-that the variation in the fit parameter correlates with the particle velocity. The obtained relation describes the flux-effect data of three types of nozzles with sizes from 1.5 to 12 mm. Within this erosion process it is suitable for interpolation between process conditions and nozzle sizes. This result may be seen as a first step to a universal model for prediction of flux effects for all types of erosion processes. (C) 1998 Elsevier Science S.A.