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-   -   Problem w/ liquid spray combustion(no reaction) (http://www.cfd-online.com/Forums/fluent/102918-problem-w-liquid-spray-combustion-no-reaction.html)

faudiS8 June 6, 2012 07:47

Problem w/ liquid spray combustion(no reaction)
 
Hi everybody
I'm modeling a complicated combustion chamber. I do not know the fuel type so I've to test some fuels.
The main question is: "I can see the spray of the liquid fuel but when I use non-premixed combustion model in species transport menu, nothing happens and after 1500 iterations I do not have correct injection too!!!"

A short history:
I start to model the combustion with gas fuel. No reaction occurs in volumetric reaction even when I patch a 2000K region! So non-premixed model was used. both equilibrium and steady flame-let has near results(adiabatic). The flame shape does not seems proper!(no data is available!). So I tried to model the combustion with liquid fuel. Using methyl-alcohol as a liquid fuel, spray is achieved by droplet model with largest time steps of 1e-5 s.
2 problems are here: 1- temperature drop due to vaporization does not seem logical!(in the particle track menu we can see temp of 100K in particles!!!!!!!WHY>!??!?!)
2- I do not know how to understand the liquid column break up.
May be answer to the following questions help me:
3- When I define injection, by using injection normal to the surface(I chose surface before), It's needed to enter a mass flux and a velocity! when I double the velocity I can see clear effects but with the flux there is nothing special happens!
4- When I actuate the combustion option is DPM menu, I can see only coal variants!!!! without this selection I cannot activate wet combustion! What should I do for simulating liquid spray combustion while non-premixed combustion and volumetric option does not result properly?!?!

Sorry for long and maybe unclear description
Thanks for any time payed.

faudiS8 June 7, 2012 13:20

hello!!!!
Does my question have any problem?!
is it clear?
:|
help pleaseee....:(


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