Atomization
 

Hi
as I know Dr Niklas.Nordin wrote dieselfoam solver by Eulerian-Lagrangian approach(discrete droplet method(DDM)).If you want to use this method you face to droplet in dense spray instead of liquid core,then why did he create an atomization model like LISA ,....?How can I use these atomization models when I have droplet in start of injection?
I think that atomization already done in DDM method.
It sounds strange.

first. the LISA model was implemented by Tommaso Lucchini.
and even though its called dieselSpray, it can be used for
any type of injector, like for instance gasoline.

There is a parameter for the parcels called liquidCore.
If this value is higher than 0.5, it does not exchange momentum/heat/mass with the gas and the atomization model
will control when the the parcel will switch to droplet-behavior, but as long as the liquidCore value is higher than 0.5 it
will be treated as if it is either in a liquid sheet or liquid core.

maybe it will be clearer if you check
src/lagrangian/dieselSpray/spray/sprayOps.C

evolve:
collisions().collideParcels(runTime_.deltaT().valu e());
move();
dispersion().disperseParcels();
inject();
atomizationLoop();
breakupLoop();


breakupLoop:
// liquidCore < 0.5 indicates discrete drops
if (elmnt().liquidCore() <= 0.5)
{
....

atomizationLoop:
// liquidCore > 0.5 indicates a liquid core
if (elmnt().liquidCore() > 0.5)
{
......


How to use them? Like you use the breakup models.

Lisa
 

Hello Dear Dr;

I am thankful for your Comprehensive response.

but there are some coefficients for this model,could you please explain these coefficients?

Cl_ , cTau_ ,Q_ , J_
are there any parameter that should be defined in sprayproperties file?

Thanks
regard

I have no idea what the model constants should be or what they do,

if you check the file

src/lagrangian/dieselSpray/spraySubModels/atomizationModel/LISA/LISA.H

you will find the references.

Accurate description in
@verbatim
P.K. Senecal, D.P. Shmidt, I. Nouar, C.J. Rutland, R.D. Reitz, M. Corradini
"Modeling high-speed viscous liquid sheet atomization"
International Journal of Multiphase Flow 25 (1999) pags. 1073-1097
@endverbatim

and

@verbatim
D.P. Schmidt, I. Nouar, P.K. Senecal, C.J. Rutland, J.K. Martin, R.D. Reitz
"Pressure-Swirl Atomization in the Near Field"
SAE Techical Paper Series 1999-01-0496
@endverbatim

Dear, Dr.,

I want to know how to define this liquid core, in the dictionary for injector model or injector type. I can't find the keyword 'liquid core' in any dictionary.

no need to define it, it is done automatically from the atomization model, via the virtual function

Foam::scalar Foam::AtomizationModel<CloudType>::initLiquidCore( ) const;

Greetings Dear Dr. Nordin
Sorry for bother with this question, as equal all my partners in this forum I'm also simulating a diesel spray, to be more specific a biodiesel spray.
I also charge all the transport properties and adjust the properties to the particular methods that NSRD functions use.
Well the question is Dr. Nordin, in the spraycloudproperties there is atomization models, blobsheet and Lisa so, there is any need to use one of them? or I can only specify the initial size and spray angle and use only the modify KHRT break up model.
Thanks a lot for your time Dr. Nordin.
Kind regards.