From 11cd2069a374acab41c07177018e76be8b04cf96 Mon Sep 17 00:00:00 2001
From: Philipp Nuske <philipp.nuske@mailbox.org>
Date: Mon, 24 Jun 2013 09:28:08 +0000
Subject: [PATCH] mpnc/diffusion & and according properties: - the maxwell
diffusion leads to a non-converging problem if used with gravity. Introduce
possibility to use Fick Diffusion in stead (default).
git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/trunk@10911 2fb0f335-1f38-0410-981e-8018bf24f1b0
---
dumux/implicit/mpnc/diffusion/diffusion.hh | 65 +++++++++++++--------
dumux/implicit/mpnc/mpncproperties.hh | 3 +
dumux/implicit/mpnc/mpncpropertydefaults.hh | 3 +
3 files changed, 46 insertions(+), 25 deletions(-)
diff --git a/dumux/implicit/mpnc/diffusion/diffusion.hh b/dumux/implicit/mpnc/diffusion/diffusion.hh
index f61e8108d5..5d470a10be 100644
--- a/dumux/implicit/mpnc/diffusion/diffusion.hh
+++ b/dumux/implicit/mpnc/diffusion/diffusion.hh
@@ -43,6 +43,8 @@ class MPNCDiffusion
enum { numComponents = GET_PROP_VALUE(TypeTag, NumComponents)};
enum { nPhaseIdx = FluidSystem::nPhaseIdx };
enum { wPhaseIdx = FluidSystem::wPhaseIdx };
+ enum { wCompIdx = FluidSystem::wCompIdx };
+ enum { nCompIdx = FluidSystem::nCompIdx };
typedef typename GET_PROP_TYPE(TypeTag, FluxVariables) FluxVariables;
typedef Dune::FieldMatrix<Scalar, numComponents, numComponents> ComponentMatrix;
@@ -52,7 +54,7 @@ public:
static void flux(ComponentVector &fluxes,
const unsigned int phaseIdx,
const FluxVariables &fluxVars,
- const Scalar molarDensity)
+ const Scalar molarDensity )
{
if (phaseIdx == nPhaseIdx)
gasFlux_(fluxes, fluxVars, molarDensity);
@@ -86,35 +88,48 @@ protected:
const FluxVariables &fluxVars,
const Scalar molarDensity)
{
- // Stefan-Maxwell equation
- //
- // See: R. Reid, et al.: "The Properties of Liquids and
- // Gases", 4th edition, 1987, McGraw-Hill, p 596
-
- // TODO: tensorial diffusion coefficients
- ComponentMatrix M(0);
-
- for (int compIIdx = 0; compIIdx < numComponents - 1; ++compIIdx) {
- for (int compJIdx = 0; compJIdx < numComponents; ++compJIdx) {
- Scalar Dij = fluxVars.porousDiffCoeffG(compIIdx, compJIdx);
- if (Dij) {
- M[compIIdx][compJIdx] += fluxVars.moleFraction(nPhaseIdx, compIIdx) / Dij;
- M[compIIdx][compIIdx] -= fluxVars.moleFraction(nPhaseIdx, compJIdx) / Dij;
+ // Alternative: use Fick Diffusion: no mutual influence of diffusion
+ if (GET_PROP_VALUE(TypeTag, UseMaxwellDiffusion) ){
+ // Stefan-Maxwell equation
+ //
+ // See: R. Reid, et al.: "The Properties of Liquids and
+ // Gases", 4th edition, 1987, McGraw-Hill, p 596
+
+ // TODO: tensorial diffusion coefficients
+ ComponentMatrix M(0);
+
+ for (int compIIdx = 0; compIIdx < numComponents - 1; ++compIIdx) {
+ for (int compJIdx = 0; compJIdx < numComponents; ++compJIdx) {
+ Scalar Dij = fluxVars.porousDiffCoeffG(compIIdx, compJIdx);
+ if (Dij) {
+ M[compIIdx][compJIdx] += fluxVars.moleFraction(nPhaseIdx, compIIdx) / Dij;
+ M[compIIdx][compIIdx] -= fluxVars.moleFraction(nPhaseIdx, compJIdx) / Dij;
+ }
}
}
- }
- for (int compIIdx = 0; compIIdx < numComponents; ++compIIdx) {
- M[numComponents - 1][compIIdx] = 1.0;
- }
+ for (int compIIdx = 0; compIIdx < numComponents; ++compIIdx) {
+ M[numComponents - 1][compIIdx] = 1.0;
+ }
- ComponentVector rightHandSide ; // see source cited above
- for (int compIIdx = 0; compIIdx < numComponents - 1; ++compIIdx) {
- rightHandSide[compIIdx] = molarDensity*(fluxVars.moleFractionGrad(nPhaseIdx, compIIdx)*fluxVars.face().normal);
- }
- rightHandSide[numComponents - 1] = 0.0;
+ ComponentVector rightHandSide ; // see source cited above
+ for (int compIIdx = 0; compIIdx < numComponents - 1; ++compIIdx) {
+ rightHandSide[compIIdx] = molarDensity*(fluxVars.moleFractionGrad(nPhaseIdx, compIIdx)*fluxVars.face().normal);
+ }
+ rightHandSide[numComponents - 1] = 0.0;
- M.solve(fluxes, rightHandSide);
+ M.solve(fluxes, rightHandSide);
+ }
+ else{// Fick Diffusion
+ for (int compIdx = 0; compIdx < numComponents; ++compIdx) {
+ // TODO: tensorial diffusion coefficients
+ const Scalar xGrad = fluxVars.moleFractionGrad(nPhaseIdx, compIdx)*fluxVars.face().normal;
+ fluxes[compIdx] =
+ - xGrad *
+ molarDensity
+ * fluxVars.porousDiffCoeffG(compIdx, nCompIdx) ; // this is == 0 for nComp==comp, i.e. no diffusion of the main component of the phase
+ }
+ }
}
// return whether a concentration can be assumed to be a trace
diff --git a/dumux/implicit/mpnc/mpncproperties.hh b/dumux/implicit/mpnc/mpncproperties.hh
index 5292d1c408..de3c264dc0 100644
--- a/dumux/implicit/mpnc/mpncproperties.hh
+++ b/dumux/implicit/mpnc/mpncproperties.hh
@@ -113,6 +113,9 @@ NEW_PROP_TAG(EnableKinetic);
//! Enable kinetic resolution of energy transfer processes?
NEW_PROP_TAG(EnableKineticEnergy);
+//! Enable Maxwell Diffusion? (If false: use Fickian Diffusion) Maxwell incorporated the mutual influences of multiple diffusing components. However, Fick seems to be more robust.
+NEW_PROP_TAG(UseMaxwellDiffusion);
+
//! Enable gravity?
NEW_PROP_TAG(ProblemEnableGravity);
diff --git a/dumux/implicit/mpnc/mpncpropertydefaults.hh b/dumux/implicit/mpnc/mpncpropertydefaults.hh
index 96d4eb6b6f..9a7e1700a4 100644
--- a/dumux/implicit/mpnc/mpncpropertydefaults.hh
+++ b/dumux/implicit/mpnc/mpncpropertydefaults.hh
@@ -144,6 +144,9 @@ SET_BOOL_PROP(MPNC, EnableKinetic, false);
//! disable kinetic energy transfer by default
SET_BOOL_PROP(MPNC, EnableKineticEnergy, false);
+//! disable Maxwell Diffusion by default: use Fick
+SET_BOOL_PROP(MPNC, UseMaxwellDiffusion, false);
+
//! enable smooth upwinding by default
SET_BOOL_PROP(MPNC, ImplicitEnableSmoothUpwinding, false);
--
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