[überschwupper]

Hello!



I want to simulate the szenario of an evaporating fluid, where the vapor is ignited and the combustion is maintaining the evaporation and vice versa. I used icoReactingMultiphaseInterFoam in OFv2106 and reactingFoam in OF9


I approached the problem by first modifying the solver icoReactingMultiPhaseInterFoam in OFv2106. I choosed this solver, because I thought adding combustion/reaction in a phase is not that complex, than adding multiphase description + phase change to a combustion solver. Unfortunately this approach failed, no matter what settings I try, the interface composition model is giving me errors. I also tried to modify those classes without success and adding entries in valid selections..

I already have seen in some publications, that they used reactingFoam for a similar problem. I tried this, but I have absolutely no clue how to do this. I tried to exchange in createFields the creation of the object "fluidReactionThermo" (multicomponent gas with reactions) with an object of type "phaseSystem" and initialize the other parts by runTimeSelection. But this is completely diffuse field for me. Then I tried to predefine the selection by directly calling the constructor directly with autoPtr<phaseSystem> fluid = new phaseSystem(arguments); and adapting the rest of the solver, which also failed.

Is there something I approach the wrong way or something I see from the wrong direction?

My questions are:
Shall I stay with icoReactingMultiphaseInterFoam or with reactingFoam - from literature aspect I would say.. reactingFoam..
Am I completely wrong with my approach to add multiphase (VoF) like this? How can I realize it in another way? Imo the runtime selection makes it really difficult for me.





Kind regards and thanks for your help in advance

[NLeb]

In ESI-OpenFOAM (you have v2106), there are a few options:

• sprayFoam - Transient solver for compressible, turbulent flow with a spray particle cloud. Uses a Lagrangian particle tracking method for modelling individual droplets of liquid and their evaporation into a surrounding continuous phase. The vapour then participates in chemical reactions specified by the user.
• reactingParcelFoam - similar to sprayFoam.
• reactingTwoPhaseEulerFoam - compressible two-phase solver which uses an Eulerian method to track the volume of fluid within each cell. Includes modelling of phase changes and chemical reactions.
• reactingFoam - as far as I am aware, this only deals with a single gaseous phase, so is probably not the right choice for you.

If your focus is on a reaction of a droplet cloud, then I recommend you use one of the Lagrangian solvers like sprayFoam (see $FOAM_TUTORIALS/lagrangian for more examples).
If, instead of a droplet cloud, you are modelling a puddle / stream of liquid or something similarly continuous, then reactingTwoPhaseEulerFoam might be better for you (see $FOAM_TUTORIALS/multiphase/reactingTwoPhaseEulerFoam for examples).

The Lagrangian solvers are much quicker and (arguably) more accurate for modelling disperse phases, so use them if possible. I myself am currently struggling with reactingTwoPhaseEulerFoam for modelling some non-disperse flow and trying to figure out how its evaporation code is working (not sure if there's a bug or I'm misunderstanding something).

More information about available Lagrangian solvers: https://www.openfoam.com/documentati...anSolvers.html
More information about available multiphase solvers: https://www.openfoam.com/documentati...seSolvers.html

Hope this helps!

[überschwupper]

Originally Posted by NLeb

In ESI-OpenFOAM (you have v2106), there are a few options:

• sprayFoam - Transient solver for compressible, turbulent flow with a spray particle cloud. Uses a Lagrangian particle tracking method for modelling individual droplets of liquid and their evaporation into a surrounding continuous phase. The vapour then participates in chemical reactions specified by the user.
• reactingParcelFoam - similar to sprayFoam.
• reactingTwoPhaseEulerFoam - compressible two-phase solver which uses an Eulerian method to track the volume of fluid within each cell. Includes modelling of phase changes and chemical reactions.
• reactingFoam - as far as I am aware, this only deals with a single gaseous phase, so is probably not the right choice for you.

If your focus is on a reaction of a droplet cloud, then I recommend you use one of the Lagrangian solvers like sprayFoam (see $FOAM_TUTORIALS/lagrangian for more examples).
If, instead of a droplet cloud, you are modelling a puddle / stream of liquid or something similarly continuous, then reactingTwoPhaseEulerFoam might be better for you (see $FOAM_TUTORIALS/multiphase/reactingTwoPhaseEulerFoam for examples).

The Lagrangian solvers are much quicker and (arguably) more accurate for modelling disperse phases, so use them if possible. I myself am currently struggling with reactingTwoPhaseEulerFoam for modelling some non-disperse flow and trying to figure out how its evaporation code is working (not sure if there's a bug or I'm misunderstanding something).

More information about available Lagrangian solvers: https://www.openfoam.com/documentati...anSolvers.html
More information about available multiphase solvers: https://www.openfoam.com/documentati...seSolvers.html

Hope this helps!

Thank you for your answer.


In my research I have found two different approaches that are used to model the process I'm interested in.
The one approach is using VoF, the other is using reactingFoam(which is Lagrangian afaik).
Since I'm mostly interested in what happens in the liquid phase close to the interface, I would say the VoF approach is the one I should stick to (thats why picked one of the interFoams derivates) or at least the Eulerian description. I mean.. Both phases are in my opinion continious and only seperated by the liquid-gas interface and coupled through the phase transfer.



I see your trouble with TwoPhaseEulerFoam. I have also took a look on this and to the evaporation part. When I have my break through here, maybe I will then be able to help you. :-)