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Old   March 22, 2013, 10:53
Default Injecting gas
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Hi all,

I want to inject different gases into a room similiar to how you inject particles. I want to inject gases like carbon monoxide and see which sections of the room have higher concentrations compared to others.

Can someone help me with injecting a gas?

Thanks
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Old   March 22, 2013, 10:55
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you will have to copy paste the material of carbon monoxide in the material list. then activate DPM and selecting what kind of injection you want. How much knowledge you have about this. if none, i suggest you to start by some tutorials about injections...
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Old   March 22, 2013, 11:13
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Ok, so I guess my question is what size diameter should I set for carbon monoxide? or any gas?

I've injected different particles before, I wasn't sure if injecting particles and gas was the same thing.

Thanks for your reply.
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Old   March 22, 2013, 11:21
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oh wait, i'm sorry your injecting gas here... my bad...i think droplet are related to liquid fuel. i've never tried to inject gas before let me look into it too. sorry about that
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Old   March 22, 2013, 11:25
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Haha no problem. I tried googling it but I couldn't really find anything on injecting different gases.
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Old   March 22, 2013, 11:49
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The automised drops of liquid in gas, or solids in liquid/gas hold themselves together as they travel. Thus, they can be represented as point masses and Langrangian equation are solved.

If you inject gases, they will try to diffuse and wander, and in doing so, will lose the initial structure of "gas particle" or whatever we call it.

Are you sure DPM is a right way for it? How about Eulerian models?

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Old   March 22, 2013, 11:51
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I am not sure if DPM is the right way. I'm relatively new to FLUENT and I've never tried injecting gas. I can look into Eulerian models and see if that is what I am looking for.

Thanks for the suggestion.
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Old   March 23, 2013, 06:40
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I do not know whether I understood what you want. If you wanna inject two or more different kind of particles, you can use User Variables -> Number of Scalars, it's like UDM for a computional cell, means UDM for every particle.
eg:
if you have two kind of particles: a and b. you can set the "Number of Scalars" as "1", when you inject particle a, set the User Variable as "1"; when you inject particle b, set the User Variable as "0" by macro:P_USER_REAL(p,0) = 0. Thus you can tell apart a and b by accessing the variable.
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Old   March 25, 2013, 11:30
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I am trying to inject a gas at the inlet and see how long it takes to reach the outlet or how long it takes to diffuse. Then I will be able to see the contour of gas concentration and where it is greatest.
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Old   April 3, 2013, 04:46
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Hello!

I have the same question.
I try to inject some water droplets from the surfaces of human body in a room. I need to inject 200 droplet per min and see the concentration in certain part of the room. I try some tutorials, but I cannot succeed. can anyone assist me here?
thanks in advance for your help.
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