How to set the maximum volume fraction of solids in a settling tank?
 

As per the title, is there a way to set the maximum volume fraction of solids for multiphaseEulerFoam?

For example, instead of maximum volume fraction (alpha in OpenFOAM) of 1.0, the highest the volume fraction could go is 0.07.

The attached case folder (settlingTank2D_base) converges however, the maximum volume fraction at the end exceeds desired value (alpha = 0.58, instead of the desired alpha = 0.07) at the settled solids region.

OpenFOAM 8 was used.

Thank you in advance for your replies!

You should use kineticTheory instead of laminar in momentumTransport.particles file.

Probably the solver will keep the max alpha at that level. However, I find 0.07 very small for a close-packed volume fraction.

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Found a tutorial case file that uses kineticTheory - fluidisedBed

Modified it to reduce the maxAlpha value (set to maxAlpha = 0.3, and also reduced initial alpha = 0.1). Converged successfully. <Attached as fluidisedBed_M1E1_base>

However, now the case behaves as if its a settling tank instead of a fluidised bed. <Attached as fluidisedBed_M0E3_base, only modified simulation to run at adjustableRunTime, otherwise unchanged>

Is there a reason for this change?

Also checked the source code for kineticTheory. It is based on work done be Welchem, 'Derivation, Implementation, and Validation of Computer Simulated Models For Gas-Solid Beds'.

Can this be used for slurry (Liquid-Solid) systems?

My understanding is that the results may be similar with the difference being Gas is compressible and Liquid is incompressible, resulting in potentially different friction factors.

P.S. If this reply is repeated, my bad, when I was checking the thread the previous reply was not found as of writing of this reply, not certain why.

Checking through the settings of fluidisedBed, I noticed it was using a modified version of kineticTheory - phasePressureModel.

An alternative tutorial case that uses kineticTheory is the LBend tutorial case