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-   -   Combustion modeling (http://www.cfd-online.com/Forums/cfx/79498-combustion-modeling.html)

SuperPahan August 25, 2010 13:11

Combustion modeling
 
I could not take a combustion process with Jet A in combustion chamber then I have a cone for Jet A liquid particles.I have applied a standard reaction of combustion. a cone for Jet A liquid particles, 3 materials. I use Particle traking model, but there is no combustion in result. May be it is because of extinction temperature, but I can't understand what is it.

Thank you for your time. Sorry for my english.( pavlenty11@gmail.com)

a.m. August 28, 2010 03:48

1) do you use standart reactions set for the JetA form templates (../CFX/etc/JetA.ccl)? 3 materials is not enough.
2) witch kind of combustion model do you use? For the first time the EDM model will be better.

SuperPahan September 2, 2010 14:44

Quote:

Originally Posted by a.m. (Post 273156)
1) do you use standart reactions set for the JetA form templates (../CFX/etc/JetA.ccl)? 3 materials is not enough.
2) witch kind of combustion model do you use? For the first time the EDM model will be better.

Yes,I using a standart reactions. I use EDM model too.I was successful when burned Jet A Liquid instead of Jet A. During that time I had my own reaction with Jet A liquid and oxigen. I set a mass fraction to 1 on fuelin boundary.
But I can't get a combustion with evaporation of Jet A liquid.

a.m. September 4, 2010 05:15

Did you try to ignite it? Set the domain temperature about 2500K for 10-15 iteration (use run in progress), then set it back.

SuperPahan September 7, 2010 14:02

Quote:

Originally Posted by a.m. (Post 273988)
Did you try to ignite it? Set the domain temperature about 2500K for 10-15 iteration (use run in progress), then set it back.

I tried to ignit particles. I set temperature 2000K. But it was, I think, only for the first iteration, but I not sure.How can I ignit particles for 10-15 iterations? Can you write me a sequense of operations?Since the 15th iteration Jet A liquid begin to evaporate.But there are no combustion products(CO2, H20).

a.m. September 8, 2010 01:12

The simplest way to ignite the particles is to set air temperature at 2000K (in pre), then, after 10-15 iteration (when CO2 and H2O has appeared), run command editor in solver and set air temperature back (usually look for FLOW:Flow Analysis 1 --> DOMAIN: name --> BOUNDARY: AIR INLET --> BOUNDARY CONDITIONS --> HEAT TRANSFER --> Static Temperature). Also you can set energy source in domain, but it is more difficult.

SuperPahan September 9, 2010 12:57

Quote:

Originally Posted by a.m. (Post 274368)
The simplest way to ignite the particles is to set air temperature at 2000K (in pre), then, after 10-15 iteration (when CO2 and H2O has appeared), run command editor in solver and set air temperature back (usually look for FLOW:Flow Analysis 1 --> DOMAIN: name --> BOUNDARY: AIR INLET --> BOUNDARY CONDITIONS --> HEAT TRANSFER --> Static Temperature). Also you can set energy source in domain, but it is more difficult.

I was successed in combustion! The main problem,I think, was in the option "1-st iteration for particles calculation"(In Solver control-Particle control).I enabled it, set 3(But default is 10). I Also set particle ignition temperature 2500K.I think, combustion may would be take plase without enabling this option but at least after 10 iterations.But I used to stop calculation, thinking that there is no combustion, after 4 iterations.Now I will be try to do a combustion to ingect particles by hollow cone.:)


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