TY - BOOK

T1 - Experimental Investigations and CFD Simulations on Particle Depositions in Gas Cyclone Separators

AU - Houben, Joseph

N1 - no embargo

PY - 2011

Y1 - 2011

N2 - Wall depositions form a problem in the practical use of cyclone separators because they influence the separation efficiency, product quality and pressure drop. Furthermore, cleaning efforts are needed more often with decreasing efficiencies in time and financial effort as a consequence. From the literature, it is examined which forces and energies have a significant contribution to the phenomenon of particle-wall adhesion, that is described by one of the two distinguished deposition models, based on conservation of energy and on the equilibrium of forces and moments, respectively. These models are implemented into computation fluid dynamics (CFD)simulations, using the commercial software package ANSYS Fluent 13.0. In the simulations, the flow field of the continuous phase is described with the Reynolds Stress Turbulence Model. Particle trajectories of the dispersed phase are calculated within a Lagrangian reference frame, for which the Discrete Phase Model with the one-way coupling and the discrete random walk model with random eddy lifetime are used. The deposition criteria are described in user defined boundary conditions. The results of the depositions found in these simulations are compared to experiments performed with a test cyclone in respect, of the relative deposited mass, positions and particle size distributions. A new model is introduced, since with the original deposition models large differences between the simulations and experiments are found. This model adapts the particle-wall impact velocity and probability in such a way that it is able to predict these quantities better, resulting in more realistic depositions during the simulations.

AB - Wall depositions form a problem in the practical use of cyclone separators because they influence the separation efficiency, product quality and pressure drop. Furthermore, cleaning efforts are needed more often with decreasing efficiencies in time and financial effort as a consequence. From the literature, it is examined which forces and energies have a significant contribution to the phenomenon of particle-wall adhesion, that is described by one of the two distinguished deposition models, based on conservation of energy and on the equilibrium of forces and moments, respectively. These models are implemented into computation fluid dynamics (CFD)simulations, using the commercial software package ANSYS Fluent 13.0. In the simulations, the flow field of the continuous phase is described with the Reynolds Stress Turbulence Model. Particle trajectories of the dispersed phase are calculated within a Lagrangian reference frame, for which the Discrete Phase Model with the one-way coupling and the discrete random walk model with random eddy lifetime are used. The deposition criteria are described in user defined boundary conditions. The results of the depositions found in these simulations are compared to experiments performed with a test cyclone in respect, of the relative deposited mass, positions and particle size distributions. A new model is introduced, since with the original deposition models large differences between the simulations and experiments are found. This model adapts the particle-wall impact velocity and probability in such a way that it is able to predict these quantities better, resulting in more realistic depositions during the simulations.

KW - Deposition Particle Separation Experiment CFD

M3 - Doctoral Thesis

ER -