โ Scribed by V.S. Babkin; A.A. Korzhavin; V.A. Bunev
No coin nor oath required. For personal study only.
Flame propagation velocities have been measured for methane-air and propane-air mixtures in four kinds of porous medium, with varying initial parameters such as pressure (from 0.06 to 2.5 MPa), equivalence ratios (0.70-1.65), and the characteristic size of cavity space (1.15-4.5 mm). All the data are well correlated by the general dependence Re = c -Pe 3, where Re is the Reynolds number based on the difference between flame propagation speed, S, and laminar burning velocity, S u, Pe is the Peclet number based on S u, and c is an experimental constant. The dependence may be derived theoretically based on two assumptions: (1) the flame propagation velocity in turbulent moving gas is determined by the maximum flow pulsation V m, S = V m + Su; and (2) at increasing values of V m, greater heat losses from the flame front into the porous medium occur until, finally, the flame is quenched. Some deviations from the general dependence observed for rich propane mixtures are explained by the manifestation of thermal-diffusive instabilities that are controlled by the Lewis number and neglected in a theoretical model.
๐ SIMILAR VOLUMES
A fully nonlinear evolution equation governing the propagation of a premixed flame through a large-scale spatially periodic shear flow is derived, and steady-state solutions are obtained numerically. The gas density is assumed to be constant across the flame, but the local normal burning speed is al
The evolution of a premixed flame under conditions of confinement is studied theoretically. The analysis is based on a hydrodynamic model in which the flame is treated as a surface of discontinuity. The flame structure is assumed to be quasi-steady with a high activation energy and a large heat rele