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CAER Seminars

Multiscale/Multiphysics simulations for multiphase gas-solids flow reactors

Sreekanth Pannala
Oak Ridge National Laboratory, Computer Science and Mathematics Division

Thursday, July 23, 2009 10:00am
Ben Bandy Conference Center
Center for Applied Energy Research

Gas-solids chemically reacting flows are omnipresent in many multiphase flow reactors in various industries like Chemical, Fossil and Nuclear. The challenging aspect of modeling these reacting flows are the wide range of both temporal and spatial scales encountered in these systems. The time scales vary from pico-seconds for the atomistic scale processes to the thousands of seconds for the device scale operations. The spatial scales vary from nano-meters at the atomistic scale to several meters at the device scale. The challenge is to accurately account and bridge (as seamlessly as possible) the length and time scales involved in the problem and the multiphysics phenomena operating at various scales. First, the problem is introduced using biomass gasifier/pyrolyser and nuclear fuel coater with sample results as examples and provide an overview of the various models currently used at the different scales.

The ongoing development of a multiphysics and multiscale mathematics framework for coupling various modeling methods over a range of scales will be presented. The development of a general wavelet-based multiscale methodology called compound wavelet matrix (CWM) for bridging spatial and temporal scales will be reported. Finally, the steps needed to generalize the current methodology for arbitrary heterogeneous chemically reacting flows or other applications involving multiscale/multiphysics coupling will be elucidated. Particular focus will be on detailing the challenges and opportunities of employing these models on massively parallel computers and how integration of HPC with complex predictive models can lead to rapid deployment of clean energy solutions based on multiphase flow reactors to the market place.