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peterdhicks August 17, 2010 11:30

Uncoupled Eulerian particle transport

I'm trying to calculate the evolution of particles within a steady pre-calculated air flow using an Eulerian model. For the problem I'm trying to solve (droplet transport through air towards impact with a solid body in aircraft icing), the volume of droplets is very low, so there's no coupling to the air, and no coupling between droplets (so droplet momentum conservation involves a drag term, but no pressure).

Firstly, can this case be done with twoPhaseEulerFoam? From my limited understanding of the source code this seems to require both phases to be unsteady.

I've been trying to extend scalarTransportFoam to add a droplet momentum conservation equation and I haven't yet got satisfactory results. The guts of my solver are

              + fvm::div(phiDrop, alpha)

            volVectorField Ur = U - UDrop;
            volScalarField magUr = mag(Ur);

            fvVectorMatrix UDropEqn
              + fvm::div(phiDrop, UDrop)
              - 0.03*magUr*Ur/diamDrop

            solve (UDropEqn);

and I was wondering if I was going about it the right way. The drag model is initial very basic for simplicity.

One of the problems I don't seem to be able to get right are the boundary conditions for the droplet velocity (UDrop) and volume fraction (alpha) on the solid body. [1] Gives a boundary condition -alpha*(UDrop dot n) > 0 on the solid surface, but I'm not sure how to replicate this in OpenFOAM. I've been trying inletOutlet and outletInlet conditions, so far without success.

Any thoughts/comments/assistance would be greatly appreciated.



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