[HeloïseM]

Hi everyone, I have a problem with the following case :

I try to simulate a rotational detonation combustor with hydrogen combustion. I'm using the ddtFoam solver from OpenFoam.
The computational domain is an annular cylinder surface which i have created with blockMesh and the checkMesh indicates that everything is okay.
I want to inject uniformly stoichiometric H2–air at 293 K at the inlet. I have part of my domains also that have specific settings of chemicals, pressure and temperture. The result of my setFieldsDict is the image below:

setfields.png

The ignition zone is set with the mixture at high temperature and pressure in order to auto-ignate.
Deflagration is modeled through a reaction progress variable c for each cell (with c 0 representing an unburnt particle and c 1 representing a burnt particle).

At the inlet the pressure should be 1bar and temperature 293K.
My courant number is set to be 0.3 max.

My simulations are crashing but i don't know why: my courant number is increasing and so DeltaT is decreasing to compensate.
Here is the error message i get :

Acoustic Courant Number mean: 9.22991e-05 max: 0.300978
deltaT = 3.65653e-10
Time = 0.00000962374, time step = 275
Quenching 9.57776e-07 % of the turbulent reaction
Calculating Riemann fluxes, second order = true
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DICPCG: Solving for Ux, Initial residual = 0.00726394, Final residual = 3.66489e-12, No Iterations 1
DICPCG: Solving for Uy, Initial residual = 0.00455063, Final residual = 2.40089e-12, No Iterations 1
DICPCG: Solving for Uz, Initial residual = 0.00314578, Final residual = 1.56327e-12, No Iterations 1
DICPCG: Solving for fH, Initial residual = 4.19317e-05, Final residual = 1.14321e-11, No Iterations 1
diagonal: Solving for tauHI, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for tauLO, Initial residual = 0, Final residual = 0, No Iterations 0
DICPCG: Solving for c, Initial residual = 3.79914e-05, Final residual = 9.35827e-14, No Iterations 1
Combustion progress = 99.13%
diagonal: Solving for rhoE, Initial residual = 0, Final residual = 0, No Iterations 0
diagonal: Solving for rhoEu, Initial residual = 0, Final residual = 0, No Iterations 0
[7]
[7]
[7] --> FOAM FATAL ERROR:
[7] Maximum number of iterations exceeded
Test = 11198.4 K,
eu_ = 1.20943e+07 J/kg, e(Test,fH) = 1.06602e+07 J/kg
[7]
[7] From function eUnburnedThermo::correct(const volScalarField& fH)
[7] in file eUnburnedThermo/eUnburnedThermo.C at line 413.
[7]
FOAM parallel run aborting
[7]
[7] #0 Foam::error:rintStack(Foam::Ostream&) at ??:?
[7] #1 Foam::error::abort() at ??:?
[7] #2 Foam::eUnburnedThermo::correct() at ??:?
[7] #3
[7] at ??:?
[7] #4 __libc_start_main in "/lib64/libc.so.6"
[7] #5
[7] at ??:?
--------------------------------------------------------------------------
MPI_ABORT was invoked on rank 7 in communicator MPI_COMM_WORLD
with errorcode 1.

NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes.
You may or may not see output from other processes, depending on
exactly when Open MPI kills them.


My files are attached to this post.
If someone know what my problem could be please ? (maybe with my pressure BC ?)



system.zip

0.zip

constant.zip

[liuyuxiang]

Originally Posted by vitorgabriel

Hello,

Thanks for ddtfoam, it's very good solver. But I'm having a problem to generate the igntion time:

Error using ThermoPhase/setTemperature (line 5)
the temperature must be positive
Error in Solution/set (line 152)
setTemperature(a,tval);
Error in uvsys (line 30)
set(gas, 'T', y(1), 'Rho', density(gas), 'Y', y(2:end));
Error in ode15s (line 579)
rhs = hinvGak*feval(odeFcn,tnew,ynew,odeArgs{:}) - Mtnew*(psi+difkp1);
Error in explosion (line 42)
out = ode15s(@uvsys,tel,y0,options,gas,mw);
Error in lookuptIgn_06CH4 (line 64)
[out] = explosion(gas0,fig_num); % constant volume explosion

I installed cantera and SDToolbox, everything is working. I generated the ddtfoamcTable_fp for methane base in cti for methane.

But the ignition time I trying all the ways and I dont solve.

Any help is welcome.

Thanks

Hello, I also encountered this problem, may I ask you to solve it? If so, can you tell me your solution.
I think it's the concentration setting of the gas

[liuyuxiang]

Originally Posted by Richardk

Hi formers,

I tried to change the fuel from hydrogen to methane, so it requires to change the ignition tables with using (lookupY_05.m and lookuptIgn_06.m))as well as some extera changes in the code, such as:
Changing the UnburnedThermo.C and eUnburnedThermo.C, as well as laminar flame speed in the compute_sl.

I have done these changes but still I cannot run a test case and even in the first time step, it goes out of janaf limit!
And I used Gulder's equation for Methane's SL.

I will appreciate if anyone can help me with these issue.


Thanks.

Can you share the changes you made or give a file of the changes? So that we can find the problem.