void Foam::noAtomization::atomizeParcel
(
parcel& p,
const scalar deltaT,
const vector& vel,
const liquidMixtureProperties& fuels
) const
{
p.liquidCore() = 0.0;
}
void blobsSheetAtomization::atomizeParcel
(
parcel& p,
const scalar deltaT,
const vector& vel,
const liquidMixture& fuels
) const
{
const PtrList<volScalarField>& Y = spray_.composition().Y();
label Ns = Y.size();
label cellI = p.cell();
scalar pressure = spray_.p()[cellI];
scalar temperature = spray_.T()[cellI];
scalar Taverage = p.T() + (temperature - p.T())/3.0;
scalar Winv = 0.0;
for(label i=0; i<Ns; i++)
{
Winv += Y[i][cellI]/spray_.gasProperties()[i].W();
}
scalar R = specie::RR*Winv;
// ideal gas law to evaluate density
scalar rhoAverage = pressure/R/Taverage;
scalar sigma = fuels.sigma(pressure, p.T(), p.X());
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
// The We and Re numbers are to be evaluated using the 1/3 rule.
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
scalar rhoFuel = fuels.rho(1.0e+5, p.T(), p.X());
scalar U = mag(p.Urel(vel));
const injectorType& it =
spray_.injectors()[label(p.injector())].properties();
vector itPosition(vector::zero);
label nHoles = it.nHoles();
if (nHoles > 1)
{
for(label i=0; i<nHoles;i++)
{
itPosition += it.position(i);
}
itPosition /= nHoles;
}
else
{
itPosition = it.position(0);
}
// const vector itPosition = it.position();
scalar lBU = B_ * sqrt
(
rhoFuel * sigma * p.d() * cos(angle_*mathematicalConstant::pi/360.0)
/ sqr(rhoAverage*U)
);
scalar pWalk = mag(p.position() - itPosition);
if(pWalk > lBU && p.liquidCore() == 1.0)
{
p.liquidCore() = 0.0;
}
}
void myLISA_3_InjPos::atomizeParcel
(
parcel& p,
const scalar deltaT,
const vector& vel,
const liquidMixture& fuels
) const
{
const PtrList<volScalarField>& Y = spray_.composition().Y();
label Ns = Y.size();
label cellI = p.cell();
scalar pressure = spray_.p()[cellI];
scalar temperature = spray_.T()[cellI];
//--------------------------------------AL____101015--------------------------------//
// scalar Taverage = p.T() + (temperature - p.T())/3.0;
scalar Taverage = temperature;
//-----------------------------------------END--------------------------------------//
scalar Winv = 0.0;
for(label i=0; i<Ns; i++)
{
Winv += Y[i][cellI]/spray_.gasProperties()[i].W();
}
scalar R = specie::RR*Winv;
// ideal gas law to evaluate density
scalar rhoAverage = pressure/R/Taverage;
//scalar nuAverage = muAverage/rhoAverage;
scalar sigma = fuels.sigma(pressure, p.T(), p.X());
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
// The We and Re numbers are to be evaluated using the 1/3 rule.
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
scalar WeberNumber = p.We(vel, rhoAverage, sigma);
scalar tau = 0.0;
scalar dL = 0.0;
scalar k = 0.0;
scalar muFuel = fuels.mu(pressure, p.T(), p.X());
scalar rhoFuel = fuels.rho(1.0e+5, p.T(), p.X());
scalar nuFuel = muFuel/rhoFuel;
vector uDir = p.U()/mag(p.U());
scalar uGas = mag(vel & uDir);
vector Ug = uGas*uDir;
/*
TL
It might be the relative velocity between Liquid and Gas, but I use the
absolute velocity of the parcel as suggested by the authors
*/
// scalar U = mag(p.Urel(vel));
scalar U = mag(p.U());
p.ct() += deltaT;
scalar Q = rhoAverage/rhoFuel;
const injectorType& it =
spray_.injectors()[label(p.injector())].properties();
if (it.nHoles() > 1)
{
Info << "Warning: This atomization model is not suitable for multihole injector." << endl
<< "Only the first hole will be used." << endl;
}
const vector direction = it.direction(0, spray_.runTime().value());
//--------------------------------CH 101108--------------------------------------------------//
// const vector itPosition = it.position(0);
const injectorModel& im = spray_.injection();
const vector itPosition = it.position(0) + im.injDist(0)*direction/mag(direction);
//------------------------------------END----------------------------------------------------//
scalar pWalk = mag(p.position() - itPosition);
// Updating liquid sheet tickness... that is the droplet diameter
// const vector direction = it.direction(0, spray_.runTime().value());
scalar h = (p.position() - itPosition) & direction;
scalar d = sqrt(sqr(pWalk)-sqr(h));
scalar time = pWalk/mag(p.U());
scalar elapsedTime = spray_.runTime().value();
scalar massFlow = it.massFlowRate(max(0.0,elapsedTime-time));
scalar hSheet = massFlow/(mathematicalConstant::pi*d*rhoFuel*mag(p.U()));
p.d() = min(hSheet,p.d());
if(WeberNumber > 27.0/16.0)
{
scalar kPos = 0.0;
scalar kNeg = Q*pow(U, 2.0)*rhoFuel/sigma;
scalar derivativePos = sqrt
(
Q*pow(U,2.0)
);
scalar derivativeNeg =
(
8.0*pow(nuFuel, 2.0)*pow(kNeg, 3.0)
+ Q*pow(U, 2.0)*kNeg
- 3.0*sigma/2.0/rhoFuel*pow(kNeg, 2.0)
)
/
sqrt
(
4.0*pow(nuFuel, 2.0)*pow(kNeg, 4.0)
+ Q*pow(U, 2.0)*pow(kNeg, 2.0)
- sigma*pow(kNeg, 3.0)/rhoFuel
)
-
4.0*nuFuel*kNeg;
scalar kOld = 0.0;
for(label i=0; i<40; i++)
{
k = kPos - (derivativePos/((derivativeNeg-derivativePos)/(kNeg-kPos)));
scalar derivativek =
(
8.0*pow(nuFuel, 2.0)*pow(k, 3.0)
+ Q*pow(U, 2.0)*k
- 3.0*sigma/2.0/rhoFuel*pow(k, 2.0)
)
/
sqrt
(
4.0*pow(nuFuel, 2.0)*pow(k, 4.0)
+ Q*pow(U, 2.0)*pow(k, 2.0)
- sigma*pow(k, 3.0)/rhoFuel
)
-
4.0*nuFuel*k;
if(derivativek > 0)
{
derivativePos = derivativek;
kPos = k;
}
else
{
derivativeNeg = derivativek;
kNeg = k;
}
if(mag(k-kOld)/k < 1e-4)
{
break;
}
kOld = k;
}
scalar omegaS =
- 2.0 * nuFuel * pow(k, 2.0)
+ sqrt
(
4.0*pow(nuFuel, 2.0)*pow(k, 4.0)
+ Q*pow(U, 2.0)*pow(k, 2.0)
- sigma*pow(k, 3.0)/rhoFuel
);
tau = cTau_/omegaS;
dL = sqrt(8.0*p.d()/k);
}
else
{
k =
rhoAverage*pow(U, 2.0)
/
2.0*sigma;
//--------------------------------------AL____101011--------------------------------//
// scalar J = pWalk*p.d()/2.0;
scalar J = time*hSheet/2.0;
//-----------------------------------------END--------------------------------------//
tau = pow(3.0*cTau_,2.0/3.0)*cbrt(J*sigma/(sqr(Q)*pow(U,4.0)*rhoFuel));
dL = sqrt(4.0*p.d()/k);
}
scalar kL =
1.0
/
(
dL *
pow(0.5 + 1.5 * muFuel/pow((rhoFuel*sigma*dL), 0.5), 0.5)
);
scalar dD = cbrt(3.0*mathematicalConstant::pi*pow(dL, 2.0)/kL);
// lisaExp is included in coeffsDict
// scalar lisaExp = 0.27;
scalar ambientPressure = 1.0e+5;
scalar pRatio = spray_.ambientPressure()/ambientPressure;
dD = dD*pow(pRatio,lisaExp_);
// modifications to take account of the flash boiling on primary breakUp
scalar pExp = 0.135;
scalar chi = 0.0;
label Nf = fuels.components().size();
scalar Td = p.T();
for(label i = 0; i < Nf ; i++)
{
if(fuels.properties()[i].pv(spray_.ambientPressure(), Td) >= 0.999*spray_.ambientPressure())
{
// The fuel is boiling.....
// Calculation of the boiling temperature
scalar tBoilingSurface = Td;
label Niter = 200;
for(label k=0; k< Niter ; k++)
{
scalar pBoil = fuels.properties()[i].pv(pressure, tBoilingSurface);
if(pBoil > pressure)
{
tBoilingSurface = tBoilingSurface - (Td-temperature)/Niter;
}
else
{
break;
}
}
scalar hl = fuels.properties()[i].hl(spray_.ambientPressure(), tBoilingSurface);
scalar iTp = fuels.properties()[i].h(spray_.ambientPressure(), Td) - spray_.ambientPressure()/fuels.properties()[i].rho(spray_.ambientPressure(), Td);
scalar iTb = fuels.properties()[i].h(spray_.ambientPressure(), tBoilingSurface) - spray_.ambientPressure()/fuels.properties()[i].rho(spray_.ambientPressure(), tBoilingSurface);
chi += p.X()[i]*(iTp-iTb)/hl;
}
}
// bounding chi
chi = max(chi, 0.0);
chi = min(chi, 1.0);
// modifing dD to take account of flash boiling
dD = dD*(1.0 - chi*pow(pRatio, -pExp));
scalar lBU = Cl_ * mag(p.U())*tau;
if(pWalk > lBU)
{
p.liquidCore() = 0.0;
// calculate the new diameter with the standard 1D Rosin Rammler distribution
//--------------------------------AL_____101012------------------------------//
// Calculation of the mean radius based on SMR rs. Coefficient factorGamma depends on nExp.
// Note that Reitz either used (Schmidt et al., 1999-01-0496) or skipped (Senecal et al.) this factor!!!
// scalar factorGamma = 0.75*sqrt(mathematicalConstant::pi); //nExp=2
scalar factorGamma = 1.;
scalar delta = dD/factorGamma;
/* dD is the SMD, and the delta is calculated using gama
function. Here we assume nExp = 2. */
// scalar delta = dD/(0.75*sqrt(mathematicalConstant::pi));
// scalar minValue = min(p.d()/20.0,dD/20.0);
scalar minValue = dD/10.0;
// delta is divided by 20 instead of 10 in order to make sure of small minValue
// scalar minValue = min(p.d(),dD/20.0);
// scalar maxValue = p.d();
scalar maxValue = dD;
// The pdf value for 4.0*delta is already very small.
// scalar maxValue = delta*4.0;
if(maxValue - minValue < SMALL)
{
// minValue = p.d()/20.0;
minValue = maxValue/20.0;
//-----------------------------------END-------------------------------------//
}
scalar range = maxValue - minValue;
scalar nExp = 3;
scalar rrd_[500];
//--------------------------------AL_____101012------------------------------//
scalar probFactorMin = exp(-pow(minValue/delta,nExp));
scalar probFactorMax = exp(-pow(maxValue/delta,nExp));
scalar probFactor = 1./(probFactorMin - probFactorMax);
//-----------------------------------END-------------------------------------//
for(label n=0; n<500; n++)
{
scalar xx = minValue + range*n/500;
//-------------------------------AL_____101012-------------------------------//
// rrd_[n] = 1 - exp(-pow(xx/delta,nExp));
rrd_[n] = (probFactorMin - exp(-pow(xx/delta,nExp)))*probFactor;
//-----------------------------------END-------------------------------------//
}
bool success = false;
scalar x = 0;
scalar y = rndGen_.scalar01();
label k = 0;
while(!success && (k<500))
{
if (rrd_[k]>y)
{
success = true;
}
k++;
}
//--------------------------------AL_____101012------------------------------//
// x = minValue + range*n/500;
x = minValue + range*(k-0.5)/500.0;
//------------------------------------END------------------------------------//
// New droplet diameter
p.d() = x;
p.ct() = 0.0;
}
}