(172c) Important Length Scales in Dense Gas-Particle Flows
AIChE Annual Meeting
2012
2012 AIChE Annual Meeting
Particle Technology Forum
Special Session to Celebrate John Chen's Career Long Accomplishments
Monday, October 29, 2012 - 3:53pm to 4:12pm
There
is a long history of studies on application of dimensional analysis to develop
scaling relations that can be employed for scale-up and scale-down of
gas-particle fluidized beds. It is now well established that two-fluid models
(TFM), with constitutive models for the stresses deduced from the kinetic
theory of granular materials, are able to capture the formation inhomogeneous
structures over a wide range of time and length scales. As resolving all these
structures in simulations of industrial scale devices is impractical, filtered
models that average over small-scale structures are currently being developed.
This has brought to the surface the issue of relevant length scales in
gas-particle flows.
In this
talk, we will review the various length scales that naturally enter in
gas-particle fluidized beds and discuss how an understanding of these scales is
being used to construct simplified filtered models. A dimensional analysis of
these filtered models then suggests a simple set of dimensionless groups that
are important to capture the dynamics of such devices when simulated on coarse
computational grids. Finally, we present simulation results, using both a TFM
and an Euler-Langrange model, which support our choice of dimensionless
parameters.
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