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How to slow down the parcels?

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Old   April 6, 2020, 13:16
Default How to slow down the parcels?
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Hi, everyone, I am simulating a high injection pressure spray at different ambient pressures with sprayFoam solver. The case is running smoothly, but some predicted results do not agree with the experimental data very well. Therefore, I list some questions here and look for the possible answers or clues.
Questions #1: the parcels goes too fast after they come out of the nozzle exit, i.e. the penetration increases too fast. I have set the pressure at "uniform 2.0e6", the density is about 20kg/m^3, the predicted spray reaches the bottom of the domain (0.08m) at 0.001s while the experimental spray penetration is only 0.065m at 0.002s.
Question #2: if the parameter "parcelBasisType" in sprayCloudProperties is mass, how to config "flowRateProfile table"? Then what's the unit of "flowRateProfile table"?
Question #3: when the simulated fuel is decane(nC10H22), will OpenFoam give the properties itself or look for them in the therm.dat, if "defaultCoeffs" is yes?
Thanks in advance!
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Old   April 6, 2020, 13:19
Default thermophysicalProperties file
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FoamFile
{
version 2.0;
format binary;
class dictionary;
location "constant";
object SprayCloudProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solution
{
active true;
coupled true;
transient yes;
cellValueSourceCorrection on;
maxCo 0.3;

sourceTerms
{
schemes
{
rho explicit 1;
U explicit 1;
Yi explicit 1;
h explicit 1;
radiation explicit 1;
}
}

interpolationSchemes
{
rho cell;
U cellPoint;
thermo:mu cell;
T cell;
Cp cell;
kappa cell;
p cell;
}

integrationSchemes
{
U Euler;
T analytical;
}
}


constantProperties
{
T0 300;

// place holders for rho0 and Cp0
// - reset from liquid properties using T0
rho0 798.13;//1000;
Cp0 4187;

constantVolume false;
}


subModels
{
particleForces
{
sphereDrag;
}

injectionModels
{
model1
{
type coneNozzleInjection;
SOI 0;
massTotal 2.38e-5;//5.85e-6;//6.0e-6;
parcelBasisType mass;
injectionMethod disc;
flowType pressureDrivenVelocity;//flowRateAndDischarge;
Pinj 70e+6;
outerDiameter 0.15e-3;//1.9e-4;
innerDiameter 0;
duration 2e-3;
position (0 0 0);//(0 0.0995 0);
direction (0 0 -1);
parcelsPerSecond 40000000;
flowRateProfile table//unit is m^3/s
(
(0 1.49e-5)//(0 1)
(0.002 1.49e-5)//(0.002 1)
);

Cd constant 0.9;

thetaInner constant 0.0;
thetaOuter constant 18.0;//10.0;

sizeDistribution
{
type RosinRammler;

RosinRammlerDistribution
{
minValue 1e-06;
maxValue 0.00013;
d 0.00013;
n 3;
}
}
}
}

dispersionModel none;//stochasticDispersionRAS;//gradientDispersionRAS;//none;

patchInteractionModel standardWallInteraction;

heatTransferModel RanzMarshall;

compositionModel singlePhaseMixture;

phaseChangeModel liquidEvaporationBoil;

surfaceFilmModel none;

atomizationModel blobsSheetAtomization;//none;

breakupModel ReitzKHRT; // ReitzDiwakar;

stochasticCollisionModel trajectory;//none;

radiation off;

standardWallInteractionCoeffs
{
type rebound;
}

RanzMarshallCoeffs
{
BirdCorrection true;
}

singlePhaseMixtureCoeffs
{
phases
(
liquid
{
C10H22 1;
}
);
}

liquidEvaporationBoilCoeffs
{
enthalpyTransfer enthalpyDifference;

activeLiquids ( C10H22 );
}

ReitzDiwakarCoeffs
{
solveOscillationEq yes;
Cbag 6;
Cb 0.785;
Cstrip 0.5;
Cs 10;
}


ReitzKHRTCoeffs
{
solveOscillationEq yes;
B0 0.61;
B1 40;
Ctau 1;
CRT 0.1;
msLimit 0.2;
WeberLimit 6;
}

TABCoeffs
{
y0 0;
yDot0 0;
Cmu 10;
Comega 8;
WeCrit 12;
}

trajectoryCoeffs
{
cSpace 1;
cTime 0.3;
coalescence on;
}

blobsSheetAtomizationCoeffs
{
B 1.0;
angle 30.0;
}
}


cloudFunctions
{}


// ************************************************** *********************** //
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Old   April 6, 2020, 13:20
Default p in 0 fold
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FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// ************************************************** *********************** //

dimensions [1 -1 -2 0 0 0 0];

internalField uniform 2e+06;

boundaryField
{
Outlet
{
type zeroGradient;
}
Walls
{
type zeroGradient;
}
Inlet
{
type zeroGradient;
}
}

// ************************************************** *********************** //
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Old   April 6, 2020, 13:25
Default Another point
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Another point is the parameters "massTotal" and "parcelsPerSecond", do they make the predicted penetration longer if I increase the former and decrease the latter? And how do they affect the computation?
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