From d054f81b5766464b11759773568575501560180c Mon Sep 17 00:00:00 2001
From: andy <a.heather@opencfd.co.uk>
Date: Mon, 18 May 2009 12:06:52 +0100
Subject: [PATCH] using 1/3 rule for surface film temperature
comments
---
.../LiquidEvaporation/LiquidEvaporation.C | 11 ++++++++---
.../LiquidEvaporation/LiquidEvaporation.H | 1 +
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/src/lagrangian/intermediate/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.C b/src/lagrangian/intermediate/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.C
index d1c3e8b8a88..f87de2537e8 100644
--- a/src/lagrangian/intermediate/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.C
+++ b/src/lagrangian/intermediate/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.C
@@ -153,6 +153,9 @@ void Foam::LiquidEvaporation<CloudType>::calculate
// Reynolds number
scalar Re = mag(Ur)*d/(nuc + ROOTVSMALL);
+ // film temperature evaluated using the 1/3 rule
+ scalar Tf = (2.0*T + Tc)/3.0;
+
// calculate mass transfer of each specie in liquid
forAll(activeLiquids_, i)
{
@@ -160,10 +163,12 @@ void Foam::LiquidEvaporation<CloudType>::calculate
label lid = liqToLiqMap_[i];
// vapour diffusivity [m2/s]
- scalar Dab = liquids_->properties()[lid].D(pc, T);
+ scalar Dab = liquids_->properties()[lid].D(pc, Tf);
// saturation pressure for species i [pa]
- scalar pSat = liquids_->properties()[lid].pv(pc, T);
+ // - carrier phase pressure assumed equal to the liquid vapour pressure
+ // close to the surface
+ scalar pSat = liquids_->properties()[lid].pv(pc, Tf);
// Schmidt number
scalar Sc = nuc/(Dab + ROOTVSMALL);
@@ -175,7 +180,7 @@ void Foam::LiquidEvaporation<CloudType>::calculate
scalar kc = Sh*Dab/(d + ROOTVSMALL);
// vapour concentration at droplet surface [kgmol/m3]
- scalar Cs = pSat/(specie::RR*T);
+ scalar Cs = pSat/(specie::RR*Tf);
// vapour concentration in bulk gas [kgmol/m3]
scalar Cinf = Xc[gid]*pc/(specie::RR*Tc);
diff --git a/src/lagrangian/intermediate/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.H b/src/lagrangian/intermediate/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.H
index 408fb3d06b7..d2a1f903dae 100644
--- a/src/lagrangian/intermediate/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.H
+++ b/src/lagrangian/intermediate/submodels/Reacting/PhaseChangeModel/LiquidEvaporation/LiquidEvaporation.H
@@ -27,6 +27,7 @@ Class
Description
Liquid evaporation model
+ - uses ideal gas assumption
\*---------------------------------------------------------------------------*/
--
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