[coastal593]

Hi All,

Quick problem with dieselFoam (1.4). I have been using it for some time with various mesh geometries with few problems. However, now I've moved to a slightly more complex 2D mesh and things are acting weird.

I have evolved the surrounding fluid motion (basically a 0.5 mach inlet and the rest is treated as atmosphere) and that works great. Then I try to add spray parcels. Works great for awhile, but then slows down systematically until eventually it simply stops ...

Number of parcels in system | 440
Injected liquid mass....... | 0.0103776 mg
Liquid Mass in system...... | 1.03557e-05 mg
SMD, Dmax.................. | 2.7153 mu, 5.63648 mu
Added gas mass = 0.0103673 mg
Evaporation Continuity Error| 1.36701e-09 mg
ExecutionTime = 3101.49 s ClockTime = 3102 s

Courant Number mean: 0.00151049 max: 0.1
deltaT = 8.33333e-10
Time = 0.000367034

Evolving Spray
Solving chemistry
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for O2, Initial residual = 0.00121118, Final residual = 1.51818e-07, No Iterations 1
DILUPBiCG: Solving for H2O, Initial residual = 0.0012151, Final residual = 4.41561e-11, No Iterations 2
DILUPBiCG: Solving for CH3OH, Initial residual = 0.00121093, Final residual = 4.31205e-11, No Iterations 2
DILUPBiCG: Solving for h, Initial residual = 0.00016995, Final residual = 1.44393e-07, No Iterations 1
DICPCG: Solving for p, Initial residual = 0.000217713, Final residual = 3.62283e-10, No Iterations 1
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 6.47539e-13, global = 2.01274e-13, cumulative = 5.49663e-11
DICPCG: Solving for p, Initial residual = 9.78815e-07, Final residual = 1.86921e-12, No Iterations 1
diagonal: Solving for rho, Initial residual = 0, Final residual = 0, No Iterations 0
time step continuity errors : sum local = 3.46536e-15, global = 1.83133e-17, cumulative = 5.49663e-11
DILUPBiCG: Solving for epsilon, Initial residual = 1.59889e-06, Final residual = 1.3528e-10, No Iterations 1
DILUPBiCG: Solving for k, Initial residual = 2.62404e-06, Final residual = 5.55037e-10, No Iterations 1

Number of parcels in system | 441
Injected liquid mass....... | 0.0103777 mg
Liquid Mass in system...... | 1.03792e-05 mg
SMD, Dmax.................. | 2.71403 mu, 5.63648 mu
Added gas mass = 0.0103673 mg
Evaporation Continuity Error| 1.37104e-09 mg
ExecutionTime = 3115.53 s ClockTime = 3116 s

Courant Number mean: 0.00151049 max: 0.1
deltaT = 8.33333e-10
Time = 0.000367035

Evolving Spray

... it just randomly stops here. it has occured to me that i am really injecting WAY too many parcels per unit time since my mesh is fairly fine and my time steps are ridiculously small. i have never figured out how to not have the sprayer inject a parcel every time step.

(injected mass is greater because i had the spray mass way down to turn it off while the fluid motion was solved before adding spray parcels)

my injector looks like ...

commonRailInjectorProps
{
position (0.0008 0.000125 0);
direction (1 0 0);
diameter 0.00008;
mass 1.41372e-8;
// mass 1e-20;
injectionPressure 125.0e+05;
temperature 295;
nParcels 1;

X
(
0.5
0.5
);

massFlowRateProfile
(
(0 1)
(5e-4 1)
);

injectionPressureProfile
(
(0 1)
(5e-4 1)
);
}

and my spray properties are pretty standard (no difference between these and the aachembomb case). my droplets are pretty small (3 microns in diameter), but i have simulated 3 micron droplets before in various other 3d meshes using the same basic setup.

i have combustion and chemistry turned off. droplets are comprised of ...

liquidFuelComponents
(
H2O
CH3OH
);

H2O H2O defaultCoeffs;
CH3OH CH3OH defaultCoeffs;

fvSolutions are the same as aachembomb with the exception of having the momemtumpredictor turned off.

any thoughts here would be greatly appreciated.

anthony