Experimental observations of the combustion of sooting fuel droplets, performed in a drop tower to create a low gravity environment, are reported. Free n-heptane droplets and suspended droplets of heptane. monochloroalkanes. and mixtures of monochloro-octane and heptane were studied. Initial droplet diameters ranged from 0.4 to I. 1 mm. The results suggest that soot may influence droplet vapori...

In this paper, we review the present state of theoretical models of thermonuclear supernovae, and compare their predicitions with the constraints derived from observations of Type Ia supernovae. The diversity of explosion mechanisms usually found in one-dimensional simulations is a direct consequence of the impossibility to resolve the flame structure under the assumption of spherical symmetry....

Spherical diffusion flames supported on a porous sphere were studied numerically and experimentally. Experiments were performed in 2.2 s and 5.2 s microgravity facilities. Numerical results were obtained from a Chemkin-based program. The program simulates flow from a porous sphere into a quiescent environment, yields both steady-state and transient results, and accounts for optically thick gas-...

Gaseous flame balls and their stability to symmetric disturbances are studied numerically and asymptotically, for large activation temperature, within a porous medium that serves only to exchange heat with the gas. Heat losses to a distant ambient environment, affecting only the gas, are taken to be radiative in nature and are represented using two alternative models. One of these treats the he...

Gas explosion and gas-coal dust are serious disasters in coal mine production. To further study the hazards of gas under different conditions, experiments were done this paper a pipeline system containing an pressure relief pipeline. Flame propagation behavior overpressure dynamics analyzed. divided into three stages: spherical flame, round-finger pointed-finger flame. front position increases ...

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 free-fall laboratory facility that provides at least 450 ms of 2 10 g. Near -limit laminar burning velocities were measured for outwardly propagating spherical stoichiometric hydrogen-air flames with...

We study the evolution of an initially spherical kernel of burned gas in a fresh reactive mixture in the presence of a gravity field. The study is carried out numerically in the framework of an axisymmetric geometry, the chemistry being modeled by an irreversible overall one-step reaction. Attention is focused on the influence of two nondimensional parameters, namely the reciprocal of the Froud...