Effect of Entrance Position on Particle Dispersion in Bidirectional Vortex Flow

Abstract

Particle dispersion in the vortex flow has been one of the most interesting subjects in recent years. Bidirectional vortex flow field is an industrial sample of rotating flow which is used to obtain advantages of better mixing and combustion. In this work penetration and dispersion quality of particles which are entering from various positions on the vortex engine walls have been numerically predicted. Head side, end side, and sidewall are considered as the entering positions. The particle has been assumed to be a rigid sphere. Initial velocity, diameter, and density of entering particles are assumed to be known. If the particle length scale is considered not to be comparable with the chamber length and if the particle number density is low, then influence of particle on the flow field is negligible and one-way solution is applicable. The solutions in each case are carried out for estimating particle trajectory and their affecting parameters. The governing equation includes affecting forces on the particle and consequently particle movement and velocity. The governing equation is converted to a set of nonlinear, coupled, second order of ordinary differential equation (ODE), and solved by a numerical scheme. The results present axial and radial trajectory of the particles in the vortex engine from the point of entering position to the wall. They show that a high centrifugal force pushes the particles towards the sidewall. This pushing force becomes more powerful when the particles approach the chamber centerline. The results imply that the best injection arrangement in the vortex engine is not the head side. The sidewall and the end side composition arrangement of injection can be the best.