[jheide]

Dear all,

I am trying to simulate an evaporating water spray in ambient air, i.e. no chemical reactions, in OpenFOAM 2.4. The only thread which is partly related could be http://www.cfd-online.com/Forums/ope...ble-flows.html . The code presented in that thread was written for OF 2.1 and it does not include evaporation.

Ideally I would like the model to include:

• Evaporation (phase change) from the Lagrangian phase (a water droplet) to the continuous phase (air/water mixture)
• Dispersion due to eulerian phase turbulence
• Two way coupling between the lagrangian/eulerian phase

The sprayFoam solver would suit this problem unless it wasn't a compressible solver. Using a density based solver for my relatively low velocities (droplets U0 ~ 100 m/s) and standard room temperature gives a poor description of the flow (temperature drops etc).

So I guess I will need to create my own solver in case there is none available (?). How should I proceed? As I see it there are two options:

1. Convert the sprayFoam solver to be incompressible
2. Add models to icoUncoupledKinematicParcelFoam

Or maybe there is another solution which is easier? If someone could explain which way would be the easiest with a short motivation it would be highly appreciated.

Thanks a lot!

[jairoandres]

Hi, I am just having the same inconvenient. I would like to ask you if you were able of converting sprayFoam to an incompressible case? I did CFD simulations using sprayFoam in a spray dryer a couple of years ago but I am very interested in knowing if you obtain sightly different results using a "incompressible" version.

[Scram_1]

Hey,
Has anyone managed to solve this problem? I want to inject water droplets in my computational domain. What I have done is coupled pimpleFoam solver with icoUncoupledKinematicLagrangianFoam which means that my solver now can do transient particle tracking. I have also added the energy equation in the modified solver. Now, I want to study the evaporation of water droplets by considering an 'incompressible' evaporation model. Can someone help me out with this?

Best,
Scram_1

[Mh.Sui]

Hi,

I also have this problem, did someone have done?

[IC01]

Hi guys. Is it 2020, anyone solved this inconvenience?

Thank you

[jairoandres]

It looks there isnt still a incompressible-flow solver for sprays, but I ask, why was it mentioned that using a compressible flow - density-based solver gives a poor description?

[einstein_zee]

Originally Posted by jairoandres

It looks there isnt still a incompressible-flow solver for sprays, but I ask, why was it mentioned that using a compressible flow - density-based solver gives a poor description?

Yeah it is also briefly mentioned in chapter 10.3 of Ferziger book that the methods for compressible flows will be inefficient for slightly compressible flows due to a different Courant number restriction... But not that they are giving a poor description though...

[jairoandres]

Originally Posted by einstein_zee

Yeah it is also briefly mentioned in chapter 10.3 of Ferziger book that the methods for compressible flows will be inefficient for slightly compressible flows due to a different Courant number restriction... But not that they are giving a poor description though...

Thank you... that's a very good read. I was looking at chap. 10.3 and I am not sure if water-spray evaporation falls within this definition (u/c <<1) as in this case, it would be (u/c <<<1). What I can surely tell you is that using the PIMPLE solver + sprayFoam, I have sometimes managed to go Co>1.0, thus not losing that much computing efficiency (besides solving many more "not-so-needed" equations).

And regarding the "poor description" mentioned in the initial post, I completely agree with you. I have always seen it as integrating the drag contribution to describe the free fall of a ball inside a vacuum chamber.