Multi species simulation

Mohankumarg12 · February 7, 2011, 09:01

Hi
I am doing a multi-species simulation which is carried our under isothermal conditions for air and methane as the two components.
The tool that I am going to use is CFX

Can I have a tutorial for this which is very much helpful.

Thanks,
Mohan.G

joey2007 · February 7, 2011, 14:38

I guess in the end it is combustor application. If yes I would recommend the combustor tutorial. For cold case you need the same steps and just omit the combustion model.

Mohankumarg12 · February 7, 2011, 23:52

Hi joey

The simulation that I am going to do is for Throttle Body Injection(TBI).Plz see the picture for clear understanding,it is just an injection mixer where the air and methane mixes and enters the combustion chamber.

Which tutorial will help me to do this and plz tell me the location where I can get it.

Thanks in advance,
Mohan.G

ghorrocks · February 8, 2011, 06:21

This is a complex model. You have transient compressible flow in the air flow, and a second species being injected from the side. There is no tutorial example for complex models like this.

There are tutorials which cover individual parts, such as compressible flow and another for multi-species gases. They are all installed with CFX.

By the way, I suspect your assumption of iso-thermal will not be valid. But I don't know your model exactly, I could be wrong.

Mohankumarg12 · February 8, 2011, 07:52

The actual process is completely unsteady but I am not doing the modelling of injection frequency,so that I am making the simulation as steady state.
The problem is not an compressible flow.

I got some idea in the coal combustion tutorial but for my problem setup I have to calculate volume fraction of air and methane as well.
How to calculate the fractions?

Thanks,
Mohan.G

ghorrocks · February 8, 2011, 18:24

Volume fractions is a multiphase thing. You will not be running a multiphase simulation, you will be running a multi-component simulation. Multi-component simulations use mass fractions.

February 7, 2011, 09:01	Multi species simulation	#1
Mohankumarg12 Member Mohankumar.G Join Date: Sep 2010 Location: Pune,India Posts: 44 Rep Power: 17	Hi I am doing a multi-species simulation which is carried our under isothermal conditions for air and methane as the two components. The tool that I am going to use is CFX Can I have a tutorial for this which is very much helpful. Thanks, Mohan.G

February 7, 2011, 14:38		#2
joey2007 Senior Member Join Date: Mar 2009 Location: Europe Posts: 169 Rep Power: 17	I guess in the end it is combustor application. If yes I would recommend the combustor tutorial. For cold case you need the same steps and just omit the combustion model. __________________ - - - - - ------------------------------------------------------------------------ Please do not forget: I am not paid for answering your questions. Thousands of issues can cause a division by zero. Please do not capture a thread, with the argument: "I have the same issue ...."

February 8, 2011, 07:52	volume fractions	#5
Mohankumarg12 Member Mohankumar.G Join Date: Sep 2010 Location: Pune,India Posts: 44 Rep Power: 17	The actual process is completely unsteady but I am not doing the modelling of injection frequency,so that I am making the simulation as steady state. The problem is not an compressible flow. I got some idea in the coal combustion tutorial but for my problem setup I have to calculate volume fraction of air and methane as well. How to calculate the fractions? Thanks, Mohan.G

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February 8, 2011, 06:21		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	This is a complex model. You have transient compressible flow in the air flow, and a second species being injected from the side. There is no tutorial example for complex models like this. There are tutorials which cover individual parts, such as compressible flow and another for multi-species gases. They are all installed with CFX. By the way, I suspect your assumption of iso-thermal will not be valid. But I don't know your model exactly, I could be wrong.

February 8, 2011, 18:24		#6
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,852 Rep Power: 144	Volume fractions is a multiphase thing. You will not be running a multiphase simulation, you will be running a multi-component simulation. Multi-component simulations use mass fractions.