[lord_kossity]

Hello!

Currently I'm using OpenFOAM-1.5.x and ran in some problem with dieselFoam.

In detail:
For reasons of creating a new solver I use the aachenBomb tutorial as playground.
Executing dieselFoam with the following controlDict

***********************
application dieselFoam;

startFrom latestTime;

startTime 0;

stopAt writeNow;

endTime 0.01;

deltaT 2.5e-06;

writeControl timeStep;

writeInterval 1;

purgeWrite 0;

writeFormat binary;

writePrecision 6;

writeCompression uncompressed;

timeFormat general;

timePrecision 6;

adjustTimeStep yes;

maxCo 0.1;

runTimeModifiable yes;

***********************

dieselFoam computes one time step without any problem. But when I try to continue computation from the last time step computation starts, but only reaches "Evolving spray" and nothing more happens, especially no Error Message is prompted.

Anybody knows how to solve this problem?

Regards,
Andreas

[henry]

Is it possible that your problem relates to

stopAt writeNow;

H

[lord_kossity]

Not in this case.

writeNow is actually set to just compute one time step in each iteration.

Although I changed the setting to

stopAt endTime;

and gave it a try. The result was the same.

Just to get it right, computation starts, when i continue from "latestTime" but dieselFoam is only working until "Evolving Spray". From thereon nothing more happens.

******************************

dietz@typhoon:~/OpenFOAM/OpenFOAM-1.5.x/tutorials/dieselFoam/aachenBomb> dieselFoam
/*---------------------------------------------------------------------------*\
| ========= | |
| \ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \ / O peration | Version: 1.5.x |
| \ / A nd | Web: http://www.OpenFOAM.org |
| \/ M anipulation | |
\*---------------------------------------------------------------------------*/
Exec : dieselFoam
Date : Jan 15 2009
Time : 09:15:12
Host : typhoon
PID : 22884
Case : /home/dietz/OpenFOAM/OpenFOAM-1.5.x/tutorials/dieselFoam/aachenBomb
nProcs : 1

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 2.94118e-06


Reading thermophysicalProperties
Selecting thermodynamics package hMixtureThermo<reactingmixture>
Selecting chemistryReader chemkinReader
Reading field U

Reading/calculating face flux field phi

Creating turbulence model.

Selecting RAS turbulence model kEpsilon
kEpsilonCoeffs
{
Cmu 0.09;
C1 1.44;
C2 1.92;
C3 -0.33;
alphah 1;
alphak 1;
alphaEps 0.76923;
muLimiter on;
Lsgs 0.0002;
}

Creating field DpDt

Constructing chemical mechanism
Selecting ODE solver SIBS
chemistryModel::chemistryModel: Number of species = 5 and reactions = 1

Reading environmentalProperties
Reading combustion properties

Constructing Spray
Selecting injectorType unitInjector
Selecting atomizationModel off
Selecting dragModel standardDragModel
Selecting evaporationModel standardEvaporationModel
Selecting heatTransferModel RanzMarshall
Selecting wallModel reflect
Selecting breakupModel ReitzKHRT
Selecting collisionModel off
Selecting dispersionModel off
Selecting injectorModel hollowConeInjector
Selecting pdfType RosinRammler
Average Velocity for injector 0: 283.853 m/s, injection pressure = 287.387 bar
Constructing three dimensional spray injection.
Courant Number mean: 1.67463e-08 max: 4.00535e-05

Starting time loop

Courant Number mean: 8.36195e-06 max: 0.02
deltaT = 0.000299599
Time = 0.000302541

Evolving Spray

******************************

The only thing I changed in the aachenBomb tutorial is the controlDict.

Does dieselFoam restart correctly on your machine?

[henry]

> Does dieselFoam restart correctly on your machine?

Generally yes but I have repeated your setup above and can reproduce the behavior, i.e. restarting after 1 time-step causes the spray evolution to go into an infinite-loop.

We are investigating....

H

[henry]

We have isolated the problem, it relates to how the time-step is adjusted on restart corresponding to the current maximum Courant number. We have pushed a fix into the 1.5.x git repository, pleas let us know if it solved your problem.

Thanks for the bug report

H

[lord_kossity]

Well, thank YOU for fixing it.

I will update my 1.5.x asap, but in the moment it seems like I can't get a connection to the repo.

I will try the following hours/days!

[lord_kossity]

Thank you, I updated my OF and simulation runs smoothly now.

[alexandrepereira]

Hi Pr. Henry

I am trying to port soot formation kinetics and thermal radiation propagation to dieselFoam ...

So I must first understand the models involved in spray modelling, dropplet atomization... etc.

So, my start will be dieselFoam... but I have a problem...

In OpenFOAM-1.3 the settings in fvSolution and fvSchemes allowed the solution of aachenBomb test case to converge... but this does not happen in dieselFoam version of OpenFOAM-1.5

Starting from the settings in the tutorial, considering the simple kinetic model of chem.inp, the solution aborts stating that the temperature is outside of the range of janafThermo...

so following the advice of another post, i have changed all the settings of laplacian discretization in fvSchemes to Gauss linear limited 01, increased the number of PISO correctors to 4 in fvSolution, and changed the settings of enthalpy discretization to Gauss upwind.

Still the same problem occurs... NOTE: I am using the mesh that came with the tutorial: hexahedral mesh built with blockmesh...

The only thing that i have not tried yet ( I am using a windows port of OpenFOAM-1.5.x compiled under mingw32, because my linux box is away in repair shop ) was to refineMesh my case, because if I do so, not even a 4GB win Vista can swallow allt the VectorFields and scalarFields that the solution will create, aborting with a badMalloc error...

Do you have any hint on what can I do to make aachenBomb of OpenFOAM-1.5.x run...?

Another (un)related question :

If I am to model an HCCI engine, considering that the premixed charge forms by rapid evaporation of a spray within the cylinder, I rather use the reactingFoam solver than the engineFoam (requiring a spark initiation fof the flame kernel ) or the dieselFoam ( which models a spray dynamics and a droplet evaporation process, which in an HCCI is very fast and essentially complete at the time of maximum compression) am I right here...?

Thanks for your answer

Best regards

Alexandre

[alexandrepereira]

Hi Pr. Henry

I am trying to port soot formation kinetics and thermal radiation propagation to dieselFoam ...

So I must first understand the models involved in spray modelling, dropplet atomization... etc.

So, my start will be dieselFoam... but I have a problem...

In OpenFOAM-1.3 the settings in fvSolution and fvSchemes allowed the solution of aachenBomb test case to converge... but this does not happen in dieselFoam version of OpenFOAM-1.5

Starting from the settings in the tutorial, considering the simple kinetic model of chem.inp, the solution aborts stating that the temperature is outside of the range of janafThermo...

so following the advice of another post, i have changed all the settings of laplacian discretization in fvSchemes to Gauss linear limited 01, increased the number of PISO correctors to 4 in fvSolution, and changed the settings of enthalpy discretization to Gauss upwind.

Still the same problem occurs... NOTE: I am using the mesh that came with the tutorial: hexahedral mesh built with blockmesh...

The only thing that i have not tried yet ( I am using a windows port of OpenFOAM-1.5.x compiled under mingw32, because my linux box is away in repair shop ) was to refineMesh my case, because if I do so, not even a 4GB win Vista can swallow allt the VectorFields and scalarFields that the solution will create, aborting with a badMalloc error...

Do you have any hint on what can I do to make aachenBomb of OpenFOAM-1.5.x run...?

Another (un)related question :

If I am to model an HCCI engine, considering that the premixed charge forms by rapid evaporation of a spray within the cylinder, I rather use the reactingFoam solver than the engineFoam (requiring a spark initiation fof the flame kernel ) or the dieselFoam ( which models a spray dynamics and a droplet evaporation process, which in an HCCI is very fast and essentially complete at the time of maximum compression) am I right here...?

Thanks for your answer

Best regards

Alexandre