Analysis of flow through packed beds WJS van der Merwe, CG du Toit, J-H Kruger North-West University Energy Postgraduate Conference 2013

Introduction What is a packed bed? How does a packed bed work? Applications. –Packed bed nuclear reactors. –Catalytic reactions. –Filtration. Design. –Pressure drop. –Heat transfer mechanisms. –Mass transfer mechanisms.

The wall effect 2-Dimensionally structured packing at the cylinder walls.

Prediction of pressure drop KTA (Nuclear Safety Standards Commission). Eisfeld and Schnitzlein (2001).

Purpose of investigation Evaluate the applicability of existing correlations which predict the pressure drop over beds with small D/d ratios. Determine the applicability of the KTA limiting curve. Explicit approach. Star-CCM+. –DEM. –CFD.

Discrete Element Modelling Generated beds in Star-CCM+ using DEM. Exported particle centre coordinates to create domains for CFD simulations.

Computational Fluid Dynamics Mesh independence study. Contact treatment. Turbulence solvers.

Validation C.A. Wentz and G. Thados (1963) Bed with a square structure.

Results

Conclusions Explicit CFD simulation results compared well with experimental measurements from literature. CFD predictions compared well with the Eisfeld and Schnitzlein correlation predictions. The KTA limiting curve is valid, but not exact. Further investigation is needed to determine a definition and criteria for the KTA limiting curve. This work is based upon research supported by the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation. Thank you.