Instability phenomena of lean hydrogen/oxygen/inert-gas premixed flames on a flat burner

Lean combustion and inert-gas addition are useful to control the burning velocity of hydrogen premixed flames, and it is well known that the cellular structure forms on the front of lean hydrogen flames owing to intrinsic instability. However, the influences of inert-gas addition on the instability phenomena of lean hydrogen premixed flames are not understood fully, and then it is needed to investigate the flame instability experimentally. In the experiments, the cellular structure and fluctuation of premixed flames on a flat burner were obtained using direct observation, laser diagnostics and light emission intensity to elucidate the characteristics of instability phenomena. As the results, the correlations of inert-gas addition, equivalence ratio and total flow rate with the characteristics of cellular flames were revealed, and the influences of these parameters on flame instability were discussed. Graphical abstract