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inhomogeneous XiFoam, problems with "ft" phase inlet

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Old   March 8, 2012, 07:10
Default inhomogeneous XiFoam, problems with "ft" phase inlet
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roberto putzu
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Dear Foamers,

I am simulating the dispersion of a "pollutant" phase in air by using the inhomogeneous mixture of the XiFoam solver (some forums suggest similar approaches). Of course I turned off the reaction.

The case is very simple. I have:
  • A flow-field with inlet (velocity) and outlet (pressure)
  • An external wall that I declared as a symmetry plane
  • A wall body in the field
  • Finally a small injection area on the body, where I impose a velocity inlet (zeroGradient pressure) and an "ft" concentration of 1.
Here is the bizarre behavior:
  • For the case here above described, the velocity and pressure field solution behave approximately as expected. A vector field coming out of the injection area reflects the velocity magnitude I imposed. Nevertheless, no "ft" phase is observed in all the field BUT at the very entry of the injection boundary condition (jump from 1 to zero in the framework of one cell)
  • I once tried and put "ft=1" at the inlet and I let run. Just to see whether I got right the use of the routine. In this second case, not only ft came out of the inlet BC. Even the injection BC started to spit out the second phase.
I first thought I was using an old version of OpenFOAM (1.6.0) and then I installe a brand new one (2.1.0) but still... the same behavior

has anyone encounter similar behaviors? is it just a bug of the software?

Thank you in advance
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Old   June 14, 2016, 09:36
Default ft does not decrease after combustion (b=0)
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Pierluigi Olmati
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In my case ft does not decrease after that combustion occurs (b-->0).
It diffuses and spreads coherently and also the combustion occurs properly but when b-->0 in a cell ft remains with a nonzero value. I expect that ft decreases during combustion and after it becomes --> 0.

Below are my key settings. Modify for inhomogeneous mixtures: fvSolution, thermophysicalProperties and setting initial condition for ft should be enough... but ft does not go to 0 after combustion.


solver PBiCG;
preconditioner DILU;
tolerance 1e-05;
relTol 0.1;

solver PBiCG;
preconditioner DILU;
tolerance 1e-05;
relTol 0;

type heheuPsiThermo;
mixture inhomogeneousMixture;
transport sutherland;
thermo janaf;
equationOfState perfectGas;
specie specie;
energy absoluteEnthalpy;

stoichiometricAirFuelMassRatio stoichiometricAirFuelMassRatio [0 0 0 0 0 0 0] 34.074;

fuel // Hydrogen H2

oxidant // Air

burntProducts // Water vapor + N2
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