CFB+wall BC for solid vel and gran temp

Umesh

Hello,

I am trying to run a multiphase flow inside a high flux high density circulating fluidized bed. I am very new to this multiphase modelling and I need a help if anybody can. I apreciate your time in advance.

Highlight of my problem and question are as follows:

Case: gas-solid two phase flow inside a riser section of Circulating Fluidized Bed with 400kg/m2-s flux and 7 m/s gas velocity.

Model chosen: Eulerian multiphase model(Kinetic theory with granular model)

Boundary conditions: I am able to set all the boundary conditions except shear stress and granular temperature conditions at the wall of the riser.

Question: At riser walls, I have set no-slip condition for gas phase.

For solid, normal velocity is zero. Tangential velocity is from a certain relation.(Tangential velocity as a function of its gradient at wall)

** HOW CAN I SET SUCH VELOCITY FOR SOLIDS AT WALLS?

Granular temp., At wall again I want to specify it as a function of its gradient such as, Granular temp at wall = A.(gradient of Gran. temp at wall)+B where A and B are cerntain constants based on simulation results.

** HOW CAN I SET SUCH GRANULAR TEMP AT RISER WALLS?

Thank you very much for your time and I hope for your sincere help.

Umesh