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-   -   Kinetic Theory in Multiphase (http://www.cfd-online.com/Forums/main/65107-kinetic-theory-multiphase.html)

mtl June 3, 2009 22:54

Kinetic Theory in Multiphase
 
Hi, I am doing research into CFD modeling of fluidized beds & cyclones. For the past one month I have been trying to use multiphase models, to no avail.

I decided to post this thread to clear some doubts on the use of kinetic theory in gas-solid simulations, and hope that it helps other researchers as well.

Please comment if any users have found the following observations contradicting

The dynamic viscosity required for a 'solid' material does not matter. No matter whether the value is from 0.05 till 1e-7 [Pa.s].

The kinetic theory will work with the granular temperature model of zero equation. The alternate algebraic equilibrium model always cause an overflow in the solver (this is the default model in CFX).

Literature suggest using Ding & Gidaspow's model of equating the granular temperature with velocity fluctuations, which is represented in another form in the zero equation anyway.

Without the kinetic theory, the simulation can still run. However, the drag coefficient would be different. Velocity profiles would remain the same as well.


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