460117 An Open-Source Adaptive-Mesh Finite-Element Framework for the Modelling of Polydispersed Flows Using Population Balances

Tuesday, November 15, 2016: 1:45 PM
Union Square 1 & 2 (Hilton San Francisco Union Square)
Gaurav Bhutani, Pablo Brito-Parada and Jan Cilliers, Department of Earth Science and Engineering, Imperial College London, London, United Kingdom

Polydispersed multiphase flows are an essential part of the chemical industry, found in applications such as minerals processing, food processing, and pharmaceutical, to name a few. Computational fluid dynamics (CFD) has become a popular tool for analysing the hydrodynamics in industrial devices (such as bubble columns and agitated mixers) in the past decade due to an improvement in the computational infrastructure and the numerical methods to model multiphase flows. However, there are certain limitations of the current modelling frameworks that prevent them from tractably simulating industrial-scale processes. The multi-scale nature of the systems leads to inter-particle interactions creating polydispersity, which is sometimes neglected in CFD models due to its expensive nature for the modelling of industrial-scale systems. This work focusses on the development of an efficient modelling framework that allows for the simulation of the polydispersed multiphase flow hydrodynamics in Fluidity, an open-source finite-element code, using adaptive meshes. The direct quadrature method of moments (DQMOM) was implemented in Fluidity as part of this work to solve the population balance equation (PBE). Rigorous verification and benchmarking is presented, followed by model validation on gravity-driven turbulent flow in bubble columns. The framework is then applied for the modelling of a flotation column, which contains two polydispersed phases—gas bubbles and solid mineral particles—in a liquid continuum. The attachment and detachment of hydrophobic mineral particles to the gas bubbles is also modelled using appropriate expressions. The above simulations are performed using fully-unstructured anisotropic adaptive meshes, which clearly show an improvement in the efficiency of the solution method. The benefit of modelling the polydispersity of gas and solid phases is also demonstrated in this work for flotation columns.

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See more of this Session: The Use of CFD in Simulation of Multiphase Mixing Processes I
See more of this Group/Topical: North American Mixing Forum