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Water level is raising as simulation progresses |
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May 31, 2022, 10:31
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Water level is raising as simulation progresses
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#1 |
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New Member
Akshay
Join Date: Jan 2020
Posts: 28
Rep Power: 8  |
I am conducting two-phase flow simulations in a separator with 3 inlets and 2 outlets using twoPhaseEulerFoam in OF version 8.
The inlet velocity BC is specified at 2 inlets and pressure outlet BC is specified at the 2 outlets. Initially, half of the separator volume is filled with water using setFieldDict. I am expecting the water level to remain constant but strangely the water level increases. I was expecting flow in = flow out, the velocity vector at the water outlet is not correctly calculating the water velocity at the outlet. I have attached my BC for U, p_rgh, alpha fields below. Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object alpha.water;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 0 0 0 0 0 0];
internalField uniform 0;
boundaryField
{
inlet1
{
type fixedValue;
value uniform 0.698;
}
inlet2
{
type fixedValue;
value uniform 0.698;
}
inlet3
{
type fixedValue;
value uniform 0.698;
}
walls
{
type zeroGradient;
}
baffle1
{
type zeroGradient;
}
baffle2
{
type zeroGradient;
}
baffle3
{
type zeroGradient;
}
outlet1
{
type inletOutlet;
phi phi.water;
inletValue uniform 1;
value uniform 1;
}
outlet2
{
type inletOutlet;
phi phi.water;
inletValue uniform 0;
value uniform 0;
}
}
// ************************************************************************* //
Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "0";
object alpha.oxygen;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 0 0 0 0 0 0];
internalField uniform 1;
boundaryField
{
inlet1
{
type fixedValue;
value uniform 0.302;
}
inlet2
{
type fixedValue;
value uniform 0.302;
}
inlet3
{
type fixedValue;
value uniform 0.302;
}
walls
{
type zeroGradient;
}
baffle1
{
type zeroGradient;
}
baffle2
{
type zeroGradient;
}
baffle3
{
type zeroGradient;
}
outlet1
{
type inletOutlet;
phi phi.oxygen;
inletValue uniform 0;
value uniform 0;
}
outlet2
{
type inletOutlet;
phi phi.oxygen;
inletValue uniform 1;
value uniform 1;
}
}
// ************************************************************************* //
Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p_rgh;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [1 -1 -2 0 0 0 0];
internalField uniform 4.01325e5;
boundaryField
{
inlet1
{
type fixedFluxPressure;
value $internalField;
}
inlet2
{
type fixedFluxPressure;
value $internalField;
}
inlet3
{
type fixedFluxPressure;
value $internalField;
}
walls
{
type fixedFluxPressure;
value $internalField;
}
baffle1
{
type fixedFluxPressure;
value $internalField;
}
baffle2
{
type fixedFluxPressure;
value $internalField;
}
baffle3
{
type fixedFluxPressure;
value $internalField;
}
outlet1 //water outlet
{
type prghPressure;
p $internalField;
value $internalField;
}
outlet2 //oxygen outlet
{
type fixedValue;
value $internalField;
}
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Code:
FoamFile
{
version 2.0;
format binary;
class volVectorField;
object U.water;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
inlet1
{
type fixedValue;
value uniform (0 0 3.83);
}
inlet2
{
type fixedValue;
value uniform (0 0 -3.83);
}
inlet3
{
type fixedValue;
value uniform (0 0 -3.83);
}
walls
{
type noSlip;
}
baffle1
{
type noSlip;
}
baffle2
{
type noSlip;
}
baffle3
{
type noSlip;
}
outlet1
{
type pressureInletOutletVelocity;
phi phi.water;
value $internalField;
}
outlet2
{
type pressureInletOutletVelocity;
phi phi.water;
value $internalField;
}
}
// ************************************************************************* //
Code:
FoamFile
{
version 2.0;
format binary;
class volVectorField;
object U.oxygen;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
inlet1
{
type fixedValue;
value uniform (0 0 1.66);
}
inlet2
{
type fixedValue;
value uniform (0 0 -1.66);
}
inlet3
{
type fixedValue;
value uniform (0 0 -1.66);
}
walls
{
type fixedValue;
value uniform (0 0 0);
}
baffle1
{
type fixedValue;
value uniform (0 0 0);
}
baffle2
{
type fixedValue;
value uniform (0 0 0);
}
baffle3
{
type fixedValue;
value uniform (0 0 0);
}
outlet1
{
type pressureInletOutletVelocity;
phi phi.oxygen;
value $internalField;
}
outlet2
{
type pressureInletOutletVelocity;
phi phi.oxygen;
value $internalField;
}
}
// ************************************************************************* //
out.0000.png out.0399.png Thank you. |
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June 23, 2022, 03:40
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I have modifies the boundary conditions
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#2 |
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New Member
Akshay
Join Date: Jan 2020
Posts: 28
Rep Power: 8 |
It is really difficult to maintain a water level inside the separator, I am playing with certain boundary conditions. Please let me know if my present adopted boundary condition is good.
Code:
{
version 2.0;
format binary;
class volVectorField;
object U.water;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
inlet1
{
type fixedValue;
value uniform (0 0 3.83);
}
inlet2
{
type fixedValue;
value uniform (0 0 -3.83);
}
inlet3
{
type fixedValue;
value uniform (0 0 -3.83);
}
walls
{
type noSlip;
}
pipes
{
type noSlip;
}
baffle1
{
type noSlip;
}
baffle2
{
type noSlip;
}
baffle3
{
type noSlip;
}
outlet1
{
type outletPhaseMeanVelocity;
UnMean 3.07;
alpha alpha.water;
value uniform (0 0 0);
}
outlet2
{
type zeroGradient;
}
}
Code:
FoamFile
{
version 2.0;
format binary;
class volVectorField;
object U.oxygen;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
inlet1
{
type fixedValue;
value uniform (0 0 1.66);
}
inlet2
{
type fixedValue;
value uniform (0 0 -1.66);
}
inlet3
{
type fixedValue;
value uniform (0 0 -1.66);
}
walls
{
type noSlip;
}
pipes
{
type noSlip;
}
baffle1
{
type noSlip;
}
baffle2
{
type noSlip;
}
baffle3
{
type noSlip;
}
outlet1
{
type zeroGradient;
}
outlet2
{
type pressureInletOutletVelocity;
phi phi.oxygen;
value $internalField;
}
}
// ************************************************************************* //
Code:
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p_rgh;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [1 -1 -2 0 0 0 0];
internalField uniform 4.01325e5;
boundaryField
{
inlet1
{
type fixedFluxPressure;
value $internalField;
}
inlet2
{
type fixedFluxPressure;
value $internalField;
}
inlet3
{
type fixedFluxPressure;
value $internalField;
}
walls
{
type fixedFluxPressure;
value $internalField;
}
pipes
{
type fixedFluxPressure;
value $internalField;
}
baffle1
{
type fixedFluxPressure;
value $internalField;
}
baffle2
{
type fixedFluxPressure;
value $internalField;
}
baffle3
{
type fixedFluxPressure;
value $internalField;
}
outlet1
{
type fixedFluxPressure;
value $internalField;
}
outlet2
{
type fixedValue;
value $internalField;
}
/*
{
type totalPressure;
p0 $internalField;
value $internalField;
// Optional entries
U U.oxygen;
phi phi;
rho rho;
}
*/
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Code:
Mesh stats
points: 188392
faces: 539938
internal faces: 516140
cells: 176193
faces per cell: 5.99387
boundary patches: 10
point zones: 0
face zones: 7
cell zones: 0
Overall number of cells of each type:
hexahedra: 164588
prisms: 7831
wedges: 0
pyramids: 0
tet wedges: 67
tetrahedra: 0
polyhedra: 3707
Breakdown of polyhedra by number of faces:
faces number of cells
4 467
5 413
6 836
7 45
8 62
9 1230
10 15
11 11
12 475
13 5
14 4
15 127
16 3
18 14
Checking topology...
Boundary definition OK.
Cell to face addressing OK.
Point usage OK.
Upper triangular ordering OK.
Face vertices OK.
Number of regions: 1 (OK).
Checking patch topology for multiply connected surfaces...
Patch Faces Points Surface topology
baffle1 1686 1713 ok (non-closed singly connected)
baffle2 1670 1702 ok (non-closed singly connected)
baffle3 1684 1715 ok (non-closed singly connected)
inlet1 59 67 ok (non-closed singly connected)
inlet2 60 68 ok (non-closed singly connected)
inlet3 57 63 ok (non-closed singly connected)
outlet1 218 232 ok (non-closed singly connected)
outlet2 16 18 ok (non-closed singly connected)
pipes 1771 1985 ok (non-closed singly connected)
walls 16577 17438 ok (non-closed singly connected)
Checking geometry...
Overall domain bounding box (-0.108 -0.348498 -0.4122) (2.8772 0.348494 0.4122)
Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
Mesh has 3 solution (non-empty) directions (1 1 1)
Boundary openness (-2.41681e-17 5.65559e-16 3.60538e-16) OK.
Max cell openness = 2.84095e-16 OK.
Max aspect ratio = 6.71026 OK.
Minimum face area = 6.42656e-07. Maximum face area = 0.000725531. Face area magnitudes OK.
Min volume = 5.69092e-08. Max volume = 1.11177e-05. Total volume = 1.04276. Cell volumes OK.
Mesh non-orthogonality Max: 44.9781 average: 5.05001
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 1.95597 OK.
Coupled point location match (average 0) OK.
Mesh OK.
End
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