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Bido14 December 10, 2012 08:16

how to set a fire
 
I want to set a fire with methane
I have a room 2 x 2 x 2 m, methane CH4 entered from the center of the bottom by a nozzle (0.25 x 0.25) at speed of 9 m/s and 1000K to ignite.
as a velocity inlet with 0.3 CH4 and 0.22 O2
I made species transport, volumetric and finite rate/eddy dissipation using methane-air mixture, inlet diffusion, and diffusion energy source

Also i use interaction with continuous phase, and update dpm sources every flow iteration(30) to have lagranrian model.

There are 4 windows (each of 125x 500 mm), 2 Pressure inlet and 2 pressure outlet with 0.23 O2 at 300 K

Sometimes it shows divergence in species 1 or Temperature, Other times after calculation it shows no (zero) Co2 or H2o which means that no combustion took place.

Please tell me how to proceed

Another thing, I need to reach a stable flame, so shall i make it stable from the begining, or make it transient and calculate till it reaches stable values.

Thanks

Yanlong Li January 2, 2013 22:36

There is a fire starting in my heart...........:D

msaeedsadeghi January 3, 2013 02:50

If you are using finite-rate species transport, you should patch 0.01 for both fuel and products and also high temperature to start fire.

Bido14 January 3, 2013 04:55

Thanks msaeedsadeghi
The Fuel temperature is 1000 K

Now The problem is that when the the methane ignites, the flame temperature distribution is conversed, i mean that the Fuel tempertaure (1000 K) is the coolest, while the rest of the room reaches 2000, 2200, 2500 K
Is there is a reason for that?
and how i can avoid it? I need to ignite the methane and have a normal temperature distribution for the flame


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