Parallel simulation of unsteady turbulent combustion is carried out for a range of precursor test problems leading to the development of a new methodology for reacting two-phase flows. Simulations are carried out using large-eddy simulations (LES) which allows full spatio-temporal resolution of all scales larger than the grid resolution with the unresolved small-scales modeled by a localized dy...

Effects of chemically-passive fire suppressants on laminar premixed hydrogen flames were investigated by combined use of microgravity experiments and computations. The experiments used a short-drop freefall laboratory facility that provides at least 450 ms of 10 2 g. Near-limit laminar burning velocities were measured for outwardly propagating spherical stoichiometric hydrogen-air flames with v...

In this study, the effect of flame intrinsic instability on the flame structural characteristics of hydrogen/air mixtures premixed at various equivalence ratios were experimentally investigated from the macroscopic and microscopic perspectives, respectively. The correlation degree and the relative deformation degree were defined to quantitatively study the global flame structural characteristic...

Laminar burning velocities and the flame response to stretch, as characterized by Markstein numbers, were determined experimentally and computationally for outwardly propagating spherical laminar premixed flames. The mixtures studied were premixed hydrogen/air/diluent and hydrogen/30% oxygen and 70% nitrogen (by volume)/diluent flames, with the latter condition of interest for pre-external vehi...

We consider the propagation of laminar premixed flames in the presence of a parallel flow whose scale is smaller than the laminar flame thickness. The study addresses fundamental aspects with relevance to flame propagation in narrow channels, to the emerging micro-combustion technology, and to the understanding of the effect of small scales in a (turbulent) flow on the flame structure. In part,...

Quasi-steady and unsteady propagations of methane and propane–air premixed flames in a mesoscale divergent channel were investigated experimentally and theoretically. The emphasis was the impact of variable cross-section area and the flame-wall coupling on the flame transition between different regimes and the onset of flame instability. Experimentally, for the first time, spinning flames were ...