Methane combustion using built in Arrhenius equation in ANSYS CFX

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  • Last Post 27 May 2019
Goenitz posted this 15 May 2019

Good day all,

My main aim is to model methane steam reforming using heat source in presence of Catalyst. For time being I am modelling methane combustion by defining my own reaction using ANSYS CFX 18.

My first problem is reaction occurs all the time even if I set activation temperature to be 3000K. Whereas in domain I assign maximum temperature of 1000K. Is there any default value which is negating my set activation temperature?

Regards

 

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Goenitz posted this 21 May 2019

I am using Fluid flow CFX

abenhadj posted this 22 May 2019

Which models are you using then? 

Best regards,

Amine

Goenitz posted this 23 May 2019

I am using Eddy dissipation model with B coefficient value 0.5 as tutorial suggested. However, now I have changed the reaction to steam reforming but results are similar. 

The reaction is taking place even when reaction rate is zero. 

Goenitz posted this 24 May 2019

Rate= A*T^beta*e^(-E/RT)

Somebody said in CFD forum (not in CFX theory guide) that T_activation is actually = E/R (activation energy/universal gas constant). So even T_activation is zero or higher rate can reach to minimum value but will not be zero.

abenhadj posted this 27 May 2019

Check if the extension temperature is larger than current temperature. Eddy dissipation model alone does only use turbulent time scale and concentration to formulate the reaction rate.

Best regards,

Amine

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