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Laminar Finite rate Model - Over predicting temperature (3300 K)

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Old   December 18, 2015, 18:43
Smile Laminar Finite rate Model - Over predicting temperature (3300 K)
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Geralt
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Hi everyone,

I am trying to model laminar diffusion flame for methane combustion.
The geometry is simple with center input methane jet (300 K , 0.5 m/s) surrounded by coflow input air(300 kelvin,0.1 m/sec)

I simulate non-reacting flows, after achieving convergence, I patch 2500 K high temperature zone for ignition and let it run with Laminar finite rate model and stiff chemistry activated.

I tried both 2 step methane-air reaction and one step methane-air reaction. In both the cases the maximum temperature predicted is 3300K and 3200 K respectively.

I used mixing law for Cp calculation of the mixture. Individual Species enthalpy are calculated by Piece wise polynomial.

I have seen many posts realted to this issue. Has anyone found a way to get temperature down to 2200 K ?
I tried similar case with Eddy disspiation model where temperature prediction was 2100K. (I know EDM is for turbulent cases)

Thank you
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Old   August 30, 2017, 06:32
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mengke zhan
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Hi,

I am also using laminar finite-rate to model a pre-mixed combustion between propane and air. However, I don't seem to get the sustained flame. The temperature returned to 300k soon after patching (3000k at the inlet). I am wondering what might be the problem here. Could you help? Thanksss!!!

Mengke

Quote:
Originally Posted by reddy.anirudh27@gmail.com View Post
Hi everyone,

I am trying to model laminar diffusion flame for methane combustion.
The geometry is simple with center input methane jet (300 K , 0.5 m/s) surrounded by coflow input air(300 kelvin,0.1 m/sec)

I simulate non-reacting flows, after achieving convergence, I patch 2500 K high temperature zone for ignition and let it run with Laminar finite rate model and stiff chemistry activated.

I tried both 2 step methane-air reaction and one step methane-air reaction. In both the cases the maximum temperature predicted is 3300K and 3200 K respectively.

I used mixing law for Cp calculation of the mixture. Individual Species enthalpy are calculated by Piece wise polynomial.

I have seen many posts realted to this issue. Has anyone found a way to get temperature down to 2200 K ?
I tried similar case with Eddy disspiation model where temperature prediction was 2100K. (I know EDM is for turbulent cases)

Thank you
mengke is offline   Reply With Quote

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combustion modeling, high temperature, laminar diffusion flame, methane-air

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