Mass Transfer and Particle Separation by Swirl-Chamber and Swirl-Tube Devices

Abstract

The goal of this investigation is to formulate, implement, and definitively validate a numerical simulation model to predict particle separation and concomitant mass transfer by means of a swirl chamber or swirl tube. The separation model encompassed three-dimensional turbulent fluid flow abetted with a particle transport model. All components of the model were used in their native form, without tuning or adaptation to accommodate the problem in question. Experiments were performed which were a precise replica of the numerical simulations in order to provide an unequivocal basis for evaluating the efficacy and validity of the simulation model. The experiments involved air flow as the carrier fluid. The particle-laden flow was ducted through a straight pipe to a three-bladed swirl generator from which the emergent swirling flow entered a settling chamber where the centrifugal forces propelled the particles toward the chamber walls. At the downstream end of the chamber, provision was made for the wall-adjacent particles to be collected. The non-collected particles exited through a central aperture. The investigation was performed for air velocities between 5 and 36 m/s. The key results that were extracted from both the numerical simulations and the experiments are the collection efficiency and the pressure drop. Comparison of the experimental and simulation results revealed very good agreement. This outcome lends unequivocal support to the numerical simulation model as a predictive tool for particle separations in swirl-chamber or swirl-tube devices.