Dilution of Methane with air

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  • Last Post 28 March 2019
TINOGK posted this 27 March 2019

Hi,

    I am trying to simulate the dilution of methane with air in a tunnel where both comes from different sources and mixes in the tunnel. But when I do VOF for the above simulation to obtain the volume fraction of methane in tunnel at different location I find that methane moves along the floor. Methane being a lighter gas is supposed to moved along the roof and moreover methane is not getting diluted with the air.

 

Why is this happening?

I have attached an image in which u can see that the methane is not getting diluted and it comes even to the floor instead of staying only along the roof

Attached Files

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abenhadj posted this 27 March 2019

Why using multiphase approach for a multicompononent single phase flow (gaseous components would rather mix instead of separate).

Best regards,

Amine

abenhadj posted this 27 March 2019

use species transport model (mass basis) then post process volume fraction.

Best regards,

Amine

TINOGK posted this 27 March 2019

Thank Amine for your help

How to post process volume fraction after species transport? I am getting only following options.

temperature

tubulance 

species

properties

wall fluces

cell info

mesh

adaptations

residual

derivatives

Nowhere it shows volume fraction...

 

How can I get a volume fraction contour as shown in the figure I attach along with this? I got that image from a reference paper. In that image they have shown volume fraction contour whereas I get only mass fraction contour in species transport

 

 

Attached Files

abenhadj posted this 27 March 2019

Create a custom field function for it. 

Best regards,

Amine

TINOGK posted this 27 March 2019

How to create custom field? As I am new to this software I amunaware of it.

Moreover whats the problem in using VOF ?

TINOGK posted this 28 March 2019

In this video it shows derivative of temperature. But how to get derivative of volume?

If not diffusion can I get a dilution using VOF?

abenhadj posted this 28 March 2019

You need to create an expression for volume fraction. That is quite basic.

Density of methane times volume fraction is equal to mixture density times mass fraction of methane.

Best regards,

Amine

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