Comparison of NO profiles in H2/N2 –air opposed jet counterflow diffusion flames: Detailed kinetics vs fluent inbuilt Thermal NO model

The present study focuses on developing a computation strategy for accurately predicting NOx emissions in laminar H2-air flames diluted with N2 using commercially available Ansys-Fluent software. The hydrogen chemistry was solved using the latest detailed kinetic model by Konnov (2019). The two approaches adopted for NOx prediction are- (1) the use of a fluent inbuilt Thermal NO model and (2) the use of detailed kinetic steps for thermal NOx containing N species from the Gri-Mech 3.0 mechanism. The fluent post-processing Thermal NO model is coupled with the solved H and OH radical concentrations field from Konnov’s (2019) mechanism for NO production. Comparing these NO profiles generated from the fluent Thermal NO model with the detailed chemistry (Gri-Mech 3.0) highlights the inconsistency of this inbuilt fluent NO model. Hence, it is concluded that detailed kinetic models containing N species should be preferred over the inbuilt fluent NO model for accurate NO predictions.