Proposal of Ergun's Equation Modified with Ratio of Straight Length to Particle Perimeter and Pipe Wall Effect

Abstract

Ergun's equation is modified by introducing the ratio of straight length to particle perimeter and the wall effect of particle bed. It can predict the pressure drop of particle bed of any shapes of coarse particles for various air velocities and pipe diameters, with an error of less than 6%. The wall effect is significant when the ratio of pipe diameter to particle diameter is smaller than 10 and the air velocity is lower than 3m/s. Ergun's equation gives poor prediction for the bed of non-spherical particles because these particles are in contact with a large area which is related to the ratio of straight length on perimeter of particles. A large deviation is found for large ratio of straight length to particle perimeter.