Hi all,

Note: here 'Theta' means, Granular temperature

Can someone help me to understand the turbulence model, k-e-kp-ep-theta, proposed by Ye Zheng. (Ref.- Yu Zheng et al., Numerical Simulation of the gas-particle turbulent flow in riser reactor based on k-e-kp-ep-Theta two fluid model, Chemical engineering Science 56, pp 6813-6822)

It looks to me similar to the k-e per phase model solved by Fluent in the case of multiphase flow eulerian-eulerian aproach.

If we solve per phase k-e model and also the PDE for Granular temp, is it the same as above k-e-kp-ep-Theta model?

Thank you very much for you time

No, it's not the same. The k-eps-k_p-eps_p-theta model keeps into account the influence of gas turbulence on the granular energy. FLUENT doens't.

Moreover, only FLUENT 6.2 implements the PDE for granular temperature, while previous versions (6.0 and 6.1) just use an algebraic semplified equation.

Regards,

ap

thank you very much, ap.

Hi ap,

Can I ask you one more question? As you know from this conversation, i m simulating a gas-solid flow inside riser. Now, I have defined riser outlet with 'Pressure Outlet' boundary condition. I realised that simple 'Outflow' BC is not appropriate. Now, in the case of Pressure Outlet boundary condition, I need to specify backflow conditions for k,eps, gran temp(solids), vol fra(solids) etc.

Now I don't know what should be the realistic BCs for these parameters? Do you have any suggestions for this? For now I have set 0 values for all assuming that I don't want to have effect of downstream conditions.

Thank you very much for your time and I appreciate your efforts.

-US

I don't know your case, but many calculations I did gave the same results using both the Outflow and the Pressure Outlet B.C.

However the backflow conditions are used only if there is a reversed flow and aren't easy to be estimated. Usually I leave the default or set them to zero too, if I have to switch to the Pressure Outlet BC.

I work on the modeling of gas-solid flows too. If you want, feel free to contact me by e-mail (ap.news@virgilio.it).

Best regards,

ap

[Angeline]

Hi ap;

Your email Id ap.news@virgilio.it is not working anymore. Can u please give me your new email Id . I want to have some discussion about gas solid flow.