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Updates from Niklas:

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Better properties for CH4N2O
Limiting the temperature to the boiling-point in parcel
This commit is contained in:
henry
2009-02-15 21:39:20 +00:00
parent c063d04a3d
commit f266f17adf
2 changed files with 53 additions and 9 deletions
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52
src/lagrangian/dieselSpray/parcel/parcel.C
View File

@ -297,7 +297,7 @@ bool Foam::parcel::move(spray& sDB)
ms() -= ms()*(oTotMass-m())/oTotMass;
// remove parcel if it is 'small'
if (m() < 1.0e-20)
if (m() < 1.0e-12)
{
keepParcel = false;
@ -574,6 +574,56 @@ void Foam::parcel::updateParcelProperties
// Prevent droplet temperature to go too low
// Mainly a numerical stability issue
Tnew = max(200.0, Tnew);
scalar Td = Tnew;
scalar pAtSurface = fuels.pv(pg, Td, X());
scalar pCompare = 0.999*pg;
scalar boiling = pAtSurface >= pCompare;
if (boiling)
{
// can not go above boiling temperature
scalar Terr = 1.0e-3;
label n=0;
scalar dT = 1.0;
scalar pOld = pAtSurface;
while (dT > Terr)
{
n++;
pAtSurface = fuels.pv(pg, Td, X());
if ((pAtSurface < pCompare) && (pOld < pCompare))
{
Td += dT;
}
else
{
if ((pAtSurface > pCompare) && (pOld > pCompare))
{
Td -= dT;
}
else
{
dT *= 0.5;
if ((pAtSurface > pCompare) && (pOld < pCompare))
{
Td -= dT;
}
else
{
Td += dT;
}
}
}
pOld = pAtSurface;
if (debug)
{
if (n>100)
{
Info << "n = " << n << ", T = " << Td << ", pv = " << pAtSurface << endl;
}
}
}
Tnew = Td;
}
}
// Evaporate droplet!

10
src/thermophysicalModels/liquids/CH4N2O/CH4N2O.H
View File

@ -90,16 +90,10 @@ public:
:
liquid(60.056, 705.0, 9.050e+6, 0.218, 0.337, 405.85, 9.3131e+1, 465.0, 1.52e-29, 0.3449, 4.7813e+4),
rho_(1230.006936, 0, 0, 0, 0, 0),
pv_(12.06, -3992.0, 0, 0, 0),
// hl_(1463034.50113228, 0, 0, 0, 0, 0),
// NN. we cant use constant heat of vapourisation, the below value is linear (sqrt) interpolation to critical temp
pv_(3015.15611544, -185497.059684, -430.223621983, 0.00017405122622, 2.0),
hl_(705.0, 2534249.0, 0.5, 0.0, 0.0, 0.0),
cp_(2006.46063673904, 0, 0, 0, 0, 0),
// NN: enthalpy, h_, is not used in the sprayModel.
// For consistency, the enthalpy is derived from hlat and hl.
// It is, however, convenient to have it available.
h_(-6154107.41641135, 2006.46063673904, 0, 0, 0, 0),
cpg_(811.875582789397, 2099.04089516451, 1627.3, 1603.63660583455, 724.41),
B_(-0.000383641934194752, 0.447249234048222, -469062.208605302, 5.5628080458239e+18, -2.3040162514986e+21),
mu_(-51.964, 3670.6, 5.7331, -5.3495e-29, 10),
@ -107,7 +101,7 @@ public:
K_(-0.4267, 0.0056903, -8.0065e-06, 1.815e-09, 0, 0),
Kg_(6.977e-05, 1.1243, 844.9, -148850),
sigma_(705.0, 1.0, 0.0, 0.0, 0.0, 0), // set to constant
D_(147.18, 20.1, 60.056, 28) // NN: Same as nHeptane
D_(147.18, 20.1, 60.056, 28) // Same as nHeptane
{}
CH4N2O
(