Data for publication: Global instability phenomenon as a physical mechanism controlling dynamics of a nitrogen-diluted hydrogen flame

Research data related to the publication "Global instability phenomenon as a physical mechanism controlling dynamics of a nitrogen-diluted hydrogen flame". In this paper, we investigate the dynamics of counter-current reacting flow under varying strengths of the counterflow and report the occurrence of global instability phenomena. This clarifies the role of global instability in the transition between attached and lifted flames. The research is performed with the help of the Large Eddy Simulation method using a high-order numerical method. The flow configuration consists of a central jet of nitrogen-diluted hydrogen fuel surrounded by an annular nozzle with a suction slot enforcing counterflow in the vicinity of the fuel stream. Suction strength is controlled by the ratio between the velocity in the suction slot and the velocity of the fuel jet. A hot oxidizer (air) provided in the region outside the co-axial nozzle causes fuel auto-ignition far from the injection system after which the flame propagates downstream. Depending on the suction strenght the flame stabilizes as attached or lifted. The flame lifting is the result of global instability appearing at increased suction in the region of counter-current flow. It is shown that the global instability induces strong toroidal vortices that create a premixed reaction zone at the flame base. This flow structuring prevents upstream flame propagation and intensifies the mixing process ensuring almost complete fuel burning in a short distance from the nozzle.The research was supported by the National Science Center in Poland (Grant No 2020/39/B/ST8/02802), the National Agency for Academic Exchange (NAWA) within the International Academic Partnerships Programme (ANIMATE project No. PPI/APM/2019/1/00062), and statutory founds (BS/PB-1-100-3011/2022/P).The readme file contains sorted filenames linked to the figures from the article.For details on file formats please refer to the readme file and documentation: https://www.tecplot.com/2016/09/16/tecplot-data-file-types-dat-plt-szplt/