failure of ignition when using chemkin imported thermodynamic and transport data

Weiqiang Liu · February 11, 2019, 17:58

hello all,

I am simulation methane air catalytic combustion in a micro-channel. The gas phase reactions are ignored and surface mechanism and thermo are imported by chemkin files.

First, I tried to use default value of gas thermo and transport in fluent data base. I can get ignited results though with some discontinuities and discrepancies with literature. In order to improve the results, I tried to import gas thermo and transport data attached with GRI3.0 mechanism. However, this time I can not get ignited results. The reaction zone just moves very slowly from the inlet to outlet and finally all the computation domain is room temperature.

The link below shows a thread I posted on ansys student community.

I am really confused about why the failure of ignition associated with chemkin imported gas thermo and transport data.

Can anybody give me some hints?

thanks

weiqiang.

Weiqiang Liu · February 11, 2019, 20:30

by the way, the energy residual is very small like 1e-4 at the beginning of iteration. Does it mean all the reactions do not happen?

February 11, 2019, 17:58	failure of ignition when using chemkin imported thermodynamic and transport data	#1
Weiqiang Liu Senior Member Weiqiang Liu Join Date: Feb 2018 Posts: 278 Rep Power: 9	hello all, I am simulation methane air catalytic combustion in a micro-channel. The gas phase reactions are ignored and surface mechanism and thermo are imported by chemkin files. First, I tried to use default value of gas thermo and transport in fluent data base. I can get ignited results though with some discontinuities and discrepancies with literature. In order to improve the results, I tried to import gas thermo and transport data attached with GRI3.0 mechanism. However, this time I can not get ignited results. The reaction zone just moves very slowly from the inlet to outlet and finally all the computation domain is room temperature. The link below shows a thread I posted on ansys student community. I am really confused about why the failure of ignition associated with chemkin imported gas thermo and transport data. Can anybody give me some hints? thanks weiqiang.

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February 11, 2019, 20:30		#2
Weiqiang Liu Senior Member Weiqiang Liu Join Date: Feb 2018 Posts: 278 Rep Power: 9	by the way, the energy residual is very small like 1e-4 at the beginning of iteration. Does it mean all the reactions do not happen?