Probabilistic analysis of particle impact at a pipe bend in pneumatic conveying

A macro-scale model of the breakage of particles at a 90 bend during dilute phase pneumatic transport is presented. Breakage results if the impact force between the particle and pipe bend exceeds the intrinsic strength of the particle. The latter is taken to be distributed according to the Weibull distribution. Impact force depends on impact velocity and this relationship is obtained by a two-phase structural model of the particle, based on the widely used Kelvin-Voigt model. The impact velocity is distributed as a result of a distribution in particle velocity and in impact angle, though the variability in the latter is shown to be the significant component. The results of the theoretical analysis are confirmed by Monte Carlo simulations. For infant formula agglomerates with typical dimensions, slightly less than 2% of the infant formula agglomerates are predicted to fail when conveyed through a simple system containing one 90 degrees bend (radius of 0.8 m) at a maximum superficial velocity of 20 m/s. (C) 2012 Elsevier B.V. All rights reserved.