A computational study of a laminar methane-air flame assisted by nanosecond repetitively pulsed discharges

Abstract
Nanosecond repetitively pulsed (NRP) discharges have been considered a promising technique for enhancing combustion efficiency and control. For successful implementation, it is necessary to understand the complex plasma-combustion interactions involving chemical, thermal, and hydrodynamic pathways. This paper aims to investigate the mechanisms enhancing a laminar methane-air flame assisted by NRP discharges by high fidelity simulations of the jet-wall burner employed in a previous experimental study. A phenomenological plasma model is used to represent the plasma energy deposition in two channels: 1) the ultrafast heating and dissociation of O2 resulting from the relaxation of electronically excited N2, and 2) slow gas heating stemming from the relaxation of N2 vibrational states. The flame displacement, key radical distribution and flame response under plasma actuation are compared with experimental results in good agreement. The computational model allows a systematic investigation of the dominant physical mechanism by isolating different pathways. It is found that the kinetic effect from atomic O production dominates the flame dynamics, while the thermal effect plays a minor role. Hydrodynamic perturbations arising from weak shock wave propagation appear to be sensitive to burner geometry and is found to be insignificant in the case under study.

Acknowledgements
This research was funded by King Abdullah University of Science and Technology (KAUST) and granted acess to the computational resources managed by KAUST Supercomputing Lab (KSL). The authors thank Dr. Davide Del Cont-Bernard, Dr. Maria Castela, Dr. Francisco E. Hernandez Perez and Ammar Alkhalifa for their valuable help

Publisher
IOP Publishing

Journal
Journal of Physics D: Applied Physics

DOI
10.1088/1361-6463/ad2836

Additional Links
https://iopscience.iop.org/article/10.1088/1361-6463/ad2836