[chunleili]

Hi, CFDers,
I am a beginner. I want to use the lagrangian/coalChemistrySolver to simulate a fludized bed.

Everything goes smoothly in the beginning. I manually gave the position of particles, changed mesh( I used the MPPIC/Goldschmidt mesh), and changed the BCs.

Then, it runned well in the first 3 or 4 steps, but stuck at the "solving the 3-D limestone1Cloud". So I guess there must be problems in limestone, and I removed the limestone cloud. I deleted the codes concerning the limestone in the coalChemistryFoam solver, and constructed my own solver. Next, I changed the cases, delete everything about limestone as well.

However, it stuck again, but at this time, it runned the first 40 steps successfully. It stuck at "solving 3-D cloud coalCloud1" for over a whole day.
(PS: I didn't use the parallel running)

Here is the message of the last full step.

(VERSION: OpenFOAM 5.0)

********************This is the reporting messege*************************
Solving 3-D cloud coalCloud1
Cloud: coalCloud1
Current number of parcels = 15
Current mass in system = 9.732826e-05
Linear momentum = (4.640577763e-22 -5.169686395e-06 -7.957195454e-11)
|Linear momentum| = 5.169686395e-06
Linear kinetic energy = 2.182705169e-06
model1:
number of parcels added = 15
mass introduced = 0.0001
Parcel fate (number, mass)
- escape = 0, 0
- stick = 0, 0
Temperature min/max = 395.934319, 3714.657715
Mass transfer phase change = 2.6e-06
Mass transfer devolatilisation = 7.174e-08
Mass transfer surface reaction = 0

diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
PIMPLE: iteration 1
smoothSolver: Solving for Ux, Initial residual = 0.02700502602, Final residual = 4.27820528e-07, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.1531300513, Final residual = 5.563320449e-06, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.3387311746, Final residual = 5.81888811e-06, No Iterations 2
smoothSolver: Solving for O2, Initial residual = 0.03372301324, Final residual = 0.0001458607168, No Iterations 1
smoothSolver: Solving for CH4, Initial residual = 1, Final residual = 0.0058086625, No Iterations 1
smoothSolver: Solving for H2, Initial residual = 1, Final residual = 0.0058086625, No Iterations 1
smoothSolver: Solving for CO2, Initial residual = 1, Final residual = 0.0058086625, No Iterations 1
smoothSolver: Solving for H2O, Initial residual = 0.01647708143, Final residual = 4.63638096e-05, No Iterations 1
smoothSolver: Solving for h, Initial residual = 0, Final residual = 0, No Iterations 0
DICPCG: Solving for G, Initial residual = 0.08545688571, Final residual = 8.279370758e-06, No Iterations 29
T gas min/max = 400, 2000
GAMG: Solving for p, Initial residual = 0.9804021843, Final residual = 0.009763620485, No Iterations 27
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 0.0003890516732, global = -4.274753778e-06, cumulative = 2.041892519e-05
GAMG: Solving for p, Initial residual = 0.2044590547, Final residual = 0.001898141125, No Iterations 24
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 7.382094053e-05, global = 6.815163749e-07, cumulative = 2.110044156e-05
GAMG: Solving for p, Initial residual = 0.01425715074, Final residual = 9.899799564e-07, No Iterations 64
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 3.253106828e-08, global = -4.282165798e-10, cumulative = 2.110001335e-05
ExecutionTime = 10.32 s ClockTime = 11 s

Courant Number mean: 0.1268739922 max: 0.2799631762
deltaT = 0.0005
Time = 0.101


Solving 3-D cloud coalCloud1
********************This is the end of reporting message*************************

Boundary Condition is as follows

********************This is the Boundary Condition**************************************
************************************************** **************************************

********************Boundary Condition of "alphat"*************************
internalField uniform 0;
boundaryField
{
top
{
type compressible::alphatWallFunction;
value uniform 0;
}
bottom
{
type compressible::alphatWallFunction;
value uniform 0;
}
walls
{
type compressible::alphatWallFunction;
value uniform 0;
}
frontAndBack
{
type wall;
}
}
********************end of "alphat"*************************

********************Boundary Condition of "CH4"*************************
internalField uniform 0;
boundaryField
{
top
{
type zeroGradient;
}
bottom
{
type zeroGradient;
}
walls
{
type zeroGradient;
}
frontAndBack
{
type zeroGradient;
}
}
********************end of "CH4"*************************

Other gases, i.e. "O2, CO2, CO, N2, H2, H2O" is exactlly the same with "CH4"

********************Boundary Condition of "G"*************************
internalField uniform 0;

boundaryField
{
top
{
type MarshakRadiation;
emissivityMode lookup;
emissivity uniform 1;
value uniform 0;
}
bottom
{
type MarshakRadiation;
emissivityMode lookup;
emissivity uniform 1;
value uniform 0;
}
walls
{
type MarshakRadiation;
emissivityMode lookup;
emissivity uniform 1;
value uniform 0;
}
frontAndBack
{
type MarshakRadiation;
emissivityMode lookup;
emissivity uniform 1;
value uniform 0;
}
}
********************end of "G"*************************

********************Boundary Condition of "p"*************************
internalField uniform 100000;

boundaryField
{
top
{
type zeroGradient;
}
bottom
{
type zeroGradient;
}
walls
{
type zeroGradient;
}
frontAndBack
{
type zeroGradient;
}
}
********************end of "p"*************************

********************Boundary Condition of "U"*************************
internalField uniform ( 0 0 0 );

boundaryField
{
top
{
type noSlip;
}
bottom
{
type noSlip;
}
walls
{
type noSlip;
}
frontAndBack
{
type noSlip;
}
}
********************end of "U"*************************

********************Boundary Condition of "T"*************************
internalField uniform 400;

boundaryField
{
top
{
type zeroGradient;
}
bottom
{
type zeroGradient;
}
walls
{
type fixedValue;
value uniform 400;
}
frontAndBack
{
type zeroGradient;
}
}
********************end of "T"*************************
********************end of all Boundary Conditions**************************************
************************************************** **************************************


The injection of particles is manually injected in the beginning,
as the original coalChemistryFoam/simplifiedSiwek example case does.
The position are: (totally 15 coalParticles)
(
(0.0 -0.03 0.15)
(0.0 0.00 0.15)
(0.0 0.03 0.15)
(0.0 -0.03 0.18)
(0.0 0.00 0.18)
(0.0 0.03 0.18)
(0.0 -0.03 0.21)
(0.0 0.00 0.21)
(0.0 0.03 0.21)
(0.0 -0.03 0.24)
(0.0 0.00 0.24)
(0.0 0.03 0.24)
(0.0 -0.03 0.27)
(0.0 0.00 0.27)
(0.0 0.03 0.27)
)

Mesh is using the example case of MPPICFoam/Goldschmidt, i.e., a 15*45 grids plane, the thick is one grid.

The controlDict is as follows:
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application coalChemistryFoam;

startFrom startTime;

startTime 0;

stopAt endTime;

endTime 0.5;

deltaT 0.0001;

writeControl adjustableRunTime;

writeInterval 0.0025;

purgeWrite 0;

writeFormat ascii;

writePrecision 10;

writeCompression off;

timeFormat general;

timePrecision 6;

runTimeModifiable true;

adjustTimeStep yes;

maxCo 1.0;

maxDeltaT 1;

// ************************************************** *********************** //

[chunleili]

I changed the BC as follows:
p: bottom uniform 1e5
N2: bottom uniform 0.79
O2: bottom uniform 0.21

At present, it goes beyond where I stuck before.

[fluid2020]

Did you find a solution for your problem? I also encountered the same problem in my simulation.

[fluid2020]

Can anyone give some comments on this point?



Any comment is appreciated.