## I am running a practice file with air is there anyway that I can change the concentration of air/material in the room?

Andre
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Joined: 09 Jun 2021, 19:05
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### I am running a practice file with air is there anyway that I can change the concentration of air/material in the room?

This example in the below I am using Ethanol.

How can I change the concentration Ethanol to the room for the file that I am using?

Solver 1
Equation = Navier-Stokes
Variable = Flow Solution[Velocity:3 Pressure:1]
Procedure = "FlowSolve" "FlowSolver"
Exec Solver = Always
Stabilize = True
Bubbles = False
Lumped Mass Matrix = False
Optimize Bandwidth = True
Steady State Convergence Tolerance = 1.0e-5
Nonlinear System Convergence Tolerance = 1.0e-7
Nonlinear System Max Iterations = 20
Nonlinear System Newton After Iterations = 3
Nonlinear System Newton After Tolerance = 1.0e-3
Nonlinear System Relaxation Factor = 1
Linear System Solver = Iterative
Linear System Iterative Method = BiCGStab
Linear System Max Iterations = 2500
Linear System Convergence Tolerance = 1.0e-9
BiCGstabl polynomial degree = 2
Linear System Preconditioning = ILU0
Linear System ILUT Tolerance = 1.0e-3
Linear System Abort Not Converged = True
Linear System Residual Output = 10
Linear System Precondition Recompute = 1
End

Material 1
Name = "Ethanol (room temperature)"
Heat expansion Coefficient = 0.25e-3
Density = 789.0
Heat Conductivity = 0.171
Heat Capacity = 2440.0
Relative Permittivity = 24.3
Sound speed = 1144.0
Viscosity = 1.074e-3
End
raback
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Joined: 22 Aug 2009, 11:57
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Location: Espoo, Finland
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### Re: I am running a practice file with air is there anyway that I can change the concentration of air/material in the roo

Hi Andre,

So you want to study the spread of ethanol droplets or vapour in air?

Generally in this kind of problem you need to know whether your concertration is so small that it does not affect the flow problem and you can solve the Navier-Stokes equations for the carried fluid. Then on that carried fluid you can solve a advection-diffusion equation.

For Elmer a challenge may be the turbulence of the carried fluid and also turbulent mixing which is not really modeled. For higher Reynolds numbers and multiphase flow OpenFOAM could offer you a better avenue.

I'm just guessing here since your original question was very economical on details. More detailed description would make understanding or your problem easier.

-Peter
Andre
Posts: 4
Joined: 09 Jun 2021, 19:05
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### Re: I am running a practice file with air is there anyway that I can change the concentration of air/material in the roo

Yes that is what I am trying to do.

This project was handed down to me and I have seen it compatible with the Navier stokes equation and I have been changing values in there.

For the modeling a room was developed to see how it flows through the air, I have vents in the room as well.

For the air, the model allows it to flow in and out of the vents, however when using ethanol it does not go through the vents.

You stated the advection-diffusion equation, I did not see a tab for that.
Do I enter this equation in manually?

Also I still don't understand where to find the concentration of the chemical I have placed in the environment. I just selected one of the materials in the materials list as they have been working better than manually entering materials.
raback
Posts: 4173
Joined: 22 Aug 2009, 11:57
Antispam: Yes
Location: Espoo, Finland
Contact:

### Re: I am running a practice file with air is there anyway that I can change the concentration of air/material in the roo

Hi

I'm happy that you gave Elmer a chance to solve your turbulent transport problem of indoor ventilation. However, I feel that there are so many challenges here that I would recommend this problem only to a developer-minded researcher that would also implement possible missing features along the way. There is a risk that you spent a lot of time banging your head to the wall and do don't accomplish the goal even with some minimal help on the forum. For OpenFOAM you can easily find references of this type of work. Hence I would have to recommend you to look at that direction.

-Peter
Andre
Posts: 4
Joined: 09 Jun 2021, 19:05
Antispam: Yes

### Re: I am running a practice file with air is there anyway that I can change the concentration of air/material in the roo

Ok.

I wont bang my head to long.
I see that openfoam is capable of being integrated with Elmer.
raback