[Pavithra]

Hello Everyone,

I am trying to model evaporation of a water droplet in open air. I am considering vapour and air diffusion.

Hence, I chose interMixingFoam as my base solver, as it can handle three fluids out of which two are miscible with each other.

I have added the temperature equation to it and have calculated the evaporation mass transfer rate (mDot).

I need add the density weighted source terms to the alpha equations.

        // Solve for alpha1
        solve
        (
        fvm::ddt(alpha1) 
        + fvc::div(alphaPhi1) 
        + mDot/rho1
        );

        // Solve for alpha2
        fvScalarMatrix alpha2Eqn
        (
            fvm::ddt(alpha2)
          + fvc::div(alphaPhi2)
          - fvm::laplacian(Dc23 + Dc32, alpha2)
          - mDot/rho2
        );
        alpha2Eqn.solve();

This compiles very well. But, it diverges immediately once I run the simulation. I understand that the source terms have to be added using Su Sp in MULES.

I read previous posts that directed to look for interCondensatingEvaporatingFoam. But, interCondensatingEvaporatingFoam has only one alphaEqn and hence it just defines one Su and Sp terms. However, in my case I have two source terms mDot/rho1 and mDot/rho2.

Some one kindly please guide how to proceed with this problem.

Thank You.

[Vitor Monteiro]

Instead of using inter, wouldn't it be better to use multiphaseEulerFoam? It has the interfaceCompositionPhaseChangeMultiphaseSystem model that could help you. See the tutorial bubbleColumnEvaporating to check how it is implemented.

[Pavithra]

Originally Posted by Vitor Monteiro

Instead of using inter, wouldn't it be better to use multiphaseEulerFoam? It has the interfaceCompositionPhaseChangeMultiphaseSystem model that could help you. See the tutorial bubbleColumnEvaporating to check how it is implemented.

Hello,

First of all, sorry for the late reply.

Thanks for the suggestion.

However, I see that the multiphaseEulerFoam does not consider phase change. (https://www.openfoam.com/documentati...EulerFoam.html).

Likewise, the bubble column tutorial in multiphaseEulerFoam folder also does not consider phase change.

Please correct me, if I am wrong.

Thank You.

[aliyah.]

Hello,

I believe icoReactingMultiphaseInterFoam can be used. For your particular case, you should use water for the soluble fraction and air and vapor for the gas part. Then choose liquid to vapor for the phase change. The* pooleEvaporation tutorial is*a good example of this. Actually, it's the example you're looking for, and just modifying the boundary conditions and geometry will result in the problem you mentioned in your question.

You can find it in the following address in openfoam.

openfoam2006/tutorials/multiphase/icoReactingMultiPhaseInterFoam/poolEvaporation

[Vitor Monteiro]

Originally Posted by Pavithra

Hello,

First of all, sorry for the late reply.

Thanks for the suggestion.

However, I see that the multiphaseEulerFoam does not consider phase change. (https://www.openfoam.com/documentati...EulerFoam.html).

Likewise, the bubble column tutorial in multiphaseEulerFoam folder also does not consider phase change.

Please correct me, if I am wrong.

Thank You.

Actually, I thing there is a interface change modeling for evaporation. See this please (https://openfoam.org/release/8/).

In that context, what does the bubbleColumnEVAPORATING tutorial in multiphaseEulerFoam do if there's not evaporation?

Sorry, correct me if I'm wrong.

[Pavithra]

Originally Posted by aliyah.

Hello,

I believe icoReactingMultiphaseInterFoam can be used. For your particular case, you should use water for the soluble fraction and air and vapor for the gas part. Then choose liquid to vapor for the phase change. The* pooleEvaporation tutorial is*a good example of this. Actually, it's the example you're looking for, and just modifying the boundary conditions and geometry will result in the problem you mentioned in your question.

You can find it in the following address in openfoam.

openfoam2006/tutorials/multiphase/icoReactingMultiPhaseInterFoam/poolEvaporation

Hi, Thanks for the suggestion. I am aware about the icoReactingMultiPhaseInterFoam. But, the phase change physics in icoReactingMultiPhaseInterFoam is based on emprirical models like Lee Model or the Schrage model. But, I am trying to implement an P_sat and T_sat dependent model. Implementation of this new model is very complex and tedious in the framework of icoReactingMultiphaseInterFoam. Hence, I intend to use the framework of interMixingFoam. interMixingFoam already can handle two miscible and one immiscible fluids. I am trying to implement the mass transfer model into this framework.

Thank You.

[Pavithra]

Originally Posted by Vitor Monteiro

Actually, I thing there is a interface change modeling for evaporation. See this please (https://openfoam.org/release/8/).

In that context, what does the bubbleColumnEVAPORATING tutorial in multiphaseEulerFoam do if there's not evaporation?

Sorry, correct me if I'm wrong.

Sorry, I am working on ESI version of openFOAM. You were talking about the foundation version.

The ESI version does not have bubble column evaporating tutorial.

I will install the foundation version of OpenFOAM and check the phase change models in multiPhaseEulerFoam.

Thanks a lot for the suggestion.

My main requirement is that I want to implement a new phase change model. It requires the inclusion of source term as described in my first post.

Thank You.

[Vitor Monteiro]

Originally Posted by Pavithra

Sorry, I am working on ESI version of openFOAM. You were talking about the foundation version.

The ESI version does not have bubble column evaporating tutorial.

I will install the foundation version of OpenFOAM and check the phase change models in multiPhaseEulerFoam.

Thank You.

That's all right. I recommend take a look on that. You mentioned implementing P_sat and T_sat dependent model, and that is exactly why I suggested interPhaseChangeModel.

Take a look on that and tell us if it was worthy.

[Graciella]

Originally Posted by Pavithra

Hello Everyone,

I am trying to model evaporation of a water droplet in open air. I am considering vapour and air diffusion.

Hence, I chose interMixingFoam as my base solver, as it can handle three fluids out of which two are miscible with each other.

I have added the temperature equation to it and have calculated the evaporation mass transfer rate (mDot).

I need add the density weighted source terms to the alpha equations.

        // Solve for alpha1
        solve
        (
        fvm::ddt(alpha1) 
        + fvc::div(alphaPhi1) 
        + mDot/rho1
        );

        // Solve for alpha2
        fvScalarMatrix alpha2Eqn
        (
            fvm::ddt(alpha2)
          + fvc::div(alphaPhi2)
          - fvm::laplacian(Dc23 + Dc32, alpha2)
          - mDot/rho2
        );
        alpha2Eqn.solve();

This compiles very well. But, it diverges immediately once I run the simulation. I understand that the source terms have to be added using Su Sp in MULES.

I read previous posts that directed to look for interCondensatingEvaporatingFoam. But, interCondensatingEvaporatingFoam has only one alphaEqn and hence it just defines one Su and Sp terms. However, in my case I have two source terms mDot/rho1 and mDot/rho2.

Some one kindly please guide how to proceed with this problem.

Thank You.

Hi Pavithra,

I hope you are good. I have the same challenge right now. Did you get to solve this issue?

Also, how did you calculate the evaporation mass transfer rate (mDot)? Did you need to have a separate file for this source code?

[zikou55]

Originally Posted by Pavithra

Thank You.

Dear Pavithra,


Please I have a question regarding your solver meltingFoam. Did you resolve the parallelization problem, because I am facing it, any advice and thank you