[EliCasto]

Hi everyone,

I am simulating a GT combustion process with CONVERGE 2.4.
I’ve run a steady-state simulations with FGM combustion modelling for both pure methane and methane with hydrogen blending. I have obtained negative NOx values in both cases.

Do you know what it could be related to?

For the emission modeling, I have used Thermal NOx model (Extended Zeldovich) with no assumption for the thermal NOx rate flag and the Prompt NOx model flag imposing equivalence ratio equal to 4.0.
The mass scaling factor converting NO to NO2 was left unchanged (1.533).
The figure in attachment shows the adopted passive NOx rates.

Thank you.

Best regards,
Elisabetta

[Pedram Tazraei]

Originally Posted by EliCasto

Hi everyone,

I am simulating a GT combustion process with CONVERGE 2.4.
I’ve run a steady-state simulations with FGM combustion modelling for both pure methane and methane with hydrogen blending. I have obtained negative NOx values in both cases.

Do you know what it could be related to?

For the emission modeling, I have used Thermal NOx model (Extended Zeldovich) with no assumption for the thermal NOx rate flag and the Prompt NOx model flag imposing equivalence ratio equal to 4.0.
The mass scaling factor converting NO to NO2 was left unchanged (1.533).
The figure in attachment shows the adopted passive NOx rates.

Thank you.

Best regards,
Elisabetta

You can try first-order solver settings to see if it solves the issue with negative NOx. If not, please contact the support team at support@convergecfd.com