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Simulation of a chemical reaction

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Old   July 2, 2013, 08:28
Default Simulation of a chemical reaction
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Nazli M
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Hello all,

im working the first time on a simulation software. I need it for my master thesis. So it is possible that i will ask for a lot of basics.

My first question:

what im doing wrong in simulation a chemical reactions?

There are two educts and two products.
I know the mass fraction in the inlet and my reaction rate.
it is a single step reaction and i use the laminar finite rate model.
In cfx-solver the mass fraction is plotted against time.
but against my expectation the educts and products are starting at the same point and end at the same point.

do you have any ideas what iam doing wrong?

Thanks
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Old   July 2, 2013, 18:58
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Glenn Horrocks
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Can you post some images of what you are modelling and your CCL?

Also, can you successfully (and accurately) solve single phase, single species models? Until you understand the basics on single phase, single species models you have no hope in getting combustion to work.
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Old   July 3, 2013, 03:58
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Nazli M
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Hi,

first thanks for your reply

I had done a lot of tutorials including exercises with single phases and single species but I really dont understood everything.

But it would great if you could check my ccl-file:
Attached Files
File Type: zip Finite rate zylinder10.zip (3.8 KB, 3 views)
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Old   July 3, 2013, 04:30
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Nazli M
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I think it is easier for you when I explain my main problem precisely.

I have problems to couple the "sources","reaction" and "expressions" with each other. And also with the mass fractions.
I know the mass fractions of my educts in the inlet and I choose water as the constraint. I started the process in steady state mode.
And than...nothing senseful came out..
the ccl-file above is without expressions...
ans this one with expressions...


Thanks again
Attached Files
File Type: zip Finite rate zylinder21.zip (4.0 KB, 5 views)
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Old   July 3, 2013, 07:18
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Glenn Horrocks
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If you have not got a good background in "simple" single phase/species modelling then do not even consider combustion modelling.

Choose some good benchmark simulations - like flow over a back step, the ahmed body, differntially heated cavity. Once you can get these simulations accurate then think about combustion modelling. You will find that even these "simple" cases are not simple at all, and getting them accurate is even harder. But if you cannot get these accurate you have no hope for combustion.
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Old   July 3, 2013, 07:25
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ok...thanks
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