May 22-27, 2016
Particulate flows encountered in fluidized beds are frequently used in industrial applications (refining, energy, chemicals/petrochemicals, pharmaceutics). The wide range of spatial scales and interactions between the phases in such systems yields a complex flow often coupled with mass and/or heat transfer. These transfer have been widely investigated in the past in an experimental and numerical manners for dilute (1, 2) and dense suspensions (3, 4).
Multi-scale modeling is a numerical approach developed to understand these phenomena from the particle scale (microscale) to process unit (macroscale). An intermediate scale (mesoscale) ranging from 104 to 108 particles is also introduced. Fluid phase is resolved using an Eulerian description while particles may be followed in a Lagrangian or an Eulerian manner. Meso/macroscale require closure laws for momentum, heat/mass transfer that can be derived either from experiments or microscale Particle-Resolved simulations (PRS).
In this work, numerical simulations of gas-solid fluidization with heat transfer are performed at the microscale (DLM/FD) and the mesoscale (Euler/Lagrange) with our massively parallel code PeliGRIFF (5). A soft-sphere model combined with a Discrete Element Method (DEM) to track particles trajectory and contacts is used at both scales and interphase drag/heat transfer closure laws derived from our own PRS are used at the mesoscale. We select a system that comprises a few thousands of particles and extract statistically averaged local and global heat transfer. We carry out a direct comparison of the predictions obtained at both scales and suggest how the mesoscale modeling might be improved to provide more accurate solutions.
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Florian Euzenat, Anthony Wachs, Abdelkader Hammouti, Pascal Fede, and Eric Climent, "Micro/Meso simulations of a fluidized bed with heat transfer" in "Fluidization XV", Jamal Chaouki, Ecole Polytechnique de Montreal, Canada Franco Berruti, Wewstern University, Canada Xiaotao Bi, UBC, Canada Ray Cocco, PSRI Inc. USA Eds, ECI Symposium Series, (2016). http://dc.engconfintl.org/fluidization_xv/172