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spray does not scale up with geometry

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Old   July 9, 2018, 16:37
Default spray does not scale up with geometry
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Hello,

I am trying to run a simulation in sprayFoam that involves injecting a liquid mixture into a container filled with air. The simulation and spray look perfectly fine when the chamber geometry is relatively small (0.005 x 0.005 x 0.01 m) workingSpray.png. However, keeping all the conditions constant, when the geometry is scaled up two orders of magnitude, which is more representative of the actual case, the spray looks extremely tiny and does not scale up in comparison with the domain InkedscaledupGeometry_LI.jpgspray.jpg.

Does anyone know why this might be the case?

I tried increasing the mass flow rate, mesh density, particle diameter, and velocity magnitude with no success. I am using a cone Injector for my case, since I have multiple injection locations. I attached pictures of the working simulation (visualized with Glyphs in ParaView) and also the unsatisfactory results. When scaled up and visualized, the spray appears as a stationary blob at the injector location at all time steps, even though the spray is actually transient and increases with time glyphVisualization.jpg.

Thanks,
Khaled
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Old   October 2, 2019, 09:45
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GwangHyeon Yu
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hi, kyounes
Could I ask you how can you set 'two' injection?

I also want to simulate two injectors

Thanks you
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Old   October 7, 2019, 15:33
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Hey, ghyu0619

I haven't picked up this work for quite a while, but I believe you can specify multiple injections in your sprayCloudProperties file by simply creating another model and copying it underneath 'injectionModels'. The snippet below should give you an idea of how to do that:

injectionModels
{
model1
{
type coneNozzleInjection;

SOI 0;
massTotal 4e-5;
duration 1.00e-03;
parcelsPerSecond 2e6;

flowType flowRateAndDischarge;
Cd 0.9;

position (5e-03 95e-03 0);
direction (0 -1 0);


parcelBasisType mass;
injectionMethod disc;
outerDiameter 1.9e-4;
innerDiameter 0;
flowRateProfile constant 1;
thetaInner constant 0.0;
thetaOuter constant 10.0;

sizeDistribution
{
type RosinRammler;

RosinRammlerDistribution
{
minValue 1e-06;
maxValue 0.00015;
d 0.00015;
n 3;
}
}
}
model2
{
type coneNozzleInjection;

SOI 0;
massTotal 4e-5;
duration 1.00e-03;
parcelsPerSecond 2e6;

flowType flowRateAndDischarge;
Cd 0.9;

position (10e-03 95e-03 0);
direction (0 -1 0);


parcelBasisType mass;
injectionMethod disc;
outerDiameter 1.9e-4;
innerDiameter 0;
flowRateProfile constant 1;
thetaInner constant 0.0;
thetaOuter constant 10.0;

sizeDistribution
{
type RosinRammler;

RosinRammlerDistribution
{
minValue 1e-06;
maxValue 0.00015;
d 0.00015;
n 3;
}
}
}

Here, I have two injectors located at x = 5 mm and x = 10 mm. You can change the parameters to suit your problem. Hope this helps!
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