This study examines the droplet combustion characteristics of three and four component miscible liquid mixtures and compares the results with an aviation fuel (Jet-A) burning under the same conditions. The configuration used in the comparison is the base case of spherical symmetry whereby the droplet and flame are spherical and concentric. Mixtures consisting of n-decane/iso-octane/toluene and ...

Thrust and fire safety are among NASA’s major concerns in the fulfillment of its mission on Mars Exploration, especially the missions that planned to bring astronauts to and back from the Red Planet. Responding to these concerns, the research studied the burning characteristics and extinction of diffusion flames in space, which are different from those on Earth due to the lack of gravity. Becau...

We report in situ, real-time detection of soot particles coated with NaCl using excimer laser fragmentation fluorescence spectroscopy (ELFFS). Carbon atom fluorescence at 248 nm and the Na D-line at 589 nm are used as signatures of soot and NaCl, respectively. Soot particles are encapsulated with a NaCl layer in a well-controlled inverted flame burner. NaCl particles are injected into the metha...

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...

In this paper we investigate performance of global communications in a particular parallel code. The code simulates dynamics of expansion of premixed spherical flames using an asymptotic model of Sivashinsky type and a spectral numerical algorithm. As a result, the code heavily relies on global all-to-all interprocessor communications implementing transposition of the distributed data array in ...

Direct Numerical Simulations (DNS) have been conducted to study the response of initially laminar spherical premixed methane–air flame kernels to successively higher turbulence intensities at five different equivalence ratios. The numerical experiments include a 16-species/25-step skeletal mechanism for methane oxidation and a multicomponent molecular transport model. Highly turbulent condition...

In this paper we investigate the acceleration of the expansion of premixed spherical flames and evolution of the cellular patterns on their surfaces. An asymptotic model is used for the simulations and a spectral numerical algorithm is employed to study flames over large time intervals. Numerous numerical experiments indicate that for large enough time intervals the acceleration of two-dimensio...

A combination of microgravity experiments and computational simulations were used to study effects of diluents on the near-limit properties of laminar, premixed hydrogen/air flames. The experiments were conducted in a short-drop free-fall laboratory facility that provided at least 450 ms of 10−2g conditions. Outwardly propagating spherical flames were used to measure near-limit laminar burning ...