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cfxusers February 26, 2002 01:24

gas-solid fluidization
 
I am using CFX4 to simulate gas-solid fluidization. In acdemic literatures, the kinetic theory of granular flow is used. The CFX4 also use it. But the document in CFX4 seems not very clear. The default model is so called "CRC model', and the alternative is the so called 'Delft model'. The correlations about kinetic theory in CFX document also puzzled me. Is it about CRC model or Delft model. Does anyone know it? Thanks.

Ribeiro March 6, 2002 10:05

Re: gas-solid fluidization
 
Hi Yang

The diference is in the GAMMA term (the dissipation of energy). Looking at the eq. 15 of the paper SIMULATION OF PARTICLES AND GAS FLOW... of Benyahia et al. from Powder Tech 112 (2000) 24-33, you can see two term that compose the GAMMA term.

In CRC Model the eq. 15 is treated as it is in paper. In Delft Model the eq. has no the term GRAD(V) - the last term. Thus it is possible to get an analytical solution.

REgards

yang March 7, 2002 08:41

Re: gas-solid fluidization
 
Dear Sir,

Thanks for your help. You mean the two model is only different in the correlation of disspation term. Delft model neglect the gradient term. But I am still a little puzzled.The CFX document (page 3-770/771. Solver) show the temperature equation (Eq. 3-383) is only composed of generation and dissipation terms, neglecting the convection and diffusion terms. This leads to an algebraic expression. Is it about CRC model or Delft model or nothing?

Yang


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