Effects of stagnation temperature on hysteresis in flame stabilization in a hydrogen-fueled strut-stabilized supersonic combustor

The effects of stagnation temperature on hysteresis in flame stabilization in a hydrogen-fueled strut-stabilized supersonic combustor are experimentally studied. The equivalence ratio (ER) is changed for the given stagnation conditions. For an average T0 of 1360 K, the three different combustion modes observed are divergent flame (CM1), strut stabilized flame (CM2), and fuel jet stabilized flame (CM3). Hysteresis is observed between CM1 and CM2 for lower ERs. For higher ERs, hysteresis is observed between CM2 and CM3. For an average T0 below 1300 K, CM1 alone is observed for all ERs. Hence, no hysteresis is observed. For T0 = 1400 K, at lower ERs, CM2 is observed for a short time. As the ER increases, CM3 is observed. It is observed that the time of the flame in the divergent section decreases with increasing T0. Hence, the variation in stagnation temperature significantly affects the hysteresis in flame stabilization modes.