The objective of the present program is to study the structure and response of steady and unsteady laminar premixed and nonpremixed flames in reduced and elevated pressure environments through (a) non-intrusive experimentation, (b) computational simulation using detailed flame and kinetic codes, and (c) asymptotic analysis with reduced kinetic mechanisms. During the reporting period progress has been made in the following projects: (1) a theoretical and experimental study of unsteady diffusion flames; (2) a computational and experimental study of hydrogen/air diffusion flames at sub- and super-atmospheric pressures; (3) an asymptotic analysis of the structure of premixed flames with volumetric heat loss; (4) asymptotic analyses of ignition in the supersonic hydrogen/air mixing layer with reduced mechanisms; (5) a new numerical algorithm for generating the ignition-extinction S-curves. A total of three reprints are appended.

The objective of the present program is to study the structure and response of steady and unsteady laminar premixed and nonpremixed flames in reduced and elevated pressure environments through (a) non-intrusive experimentation, (b) computational simulation using detailed flame and kinetic codes, and (c) asymptotic analysis with reduced kinetic mechanisms. During the reporting period progress has been made in the following projects: (1) a theoretical and experimental study of unsteady diffusion flames; (2) a computational and experimental study of methane/air flames at elevated pressures; (3) an asymptotic analysis of the structure of methane/air premixed flames with reduced chemistry; (4) an asymptotic analyses of the extinction of laminar premixed flames with volumetric heat loss and chain mechanisms; and (5) asymptotic analyses of ignition in the supersonic laminar flat-plate boundary layer and mixng layer. A total of five reprints are appended.

The objective of the present program is to study the structure and response of steady and unsteady laminar premixed and nonpremixed flames in reduced and elevated pressure environments through (a) non-intrusive experimentation, (b) computational simulation using detailed flame and kinetic codes, and (c) asymptotic analysis with reduced kinetic mechanisms. During the reporting period progress has been made in the following projects: (1) a theoretical and experimental study of unsteady diffusion flames; (2) a computational and experimental study of methane/air flames at elevated pressures; (3) an asymptotic analysis of the structure of methane/air premixed flames with reduced chemistry; (4) an asymptotic analysis of the extinction of laminar premixed flames with volumetric heat loss and chain mechanisms; and (5) asymptotic analyses of ignition in the supersonic laminar flat-plate boundary layer and mixing layer. A total of five reprints are appended. Flames, High-pressure combustion, Unsteady combustion, Reduced mechanisms, Methane-air flames, Extinction, Supersonic combustion.

Partial contents: Supercritical droplet behavior; Fundamentals of acoustic instabilities in liquid-propellant rockets; Modeling liquid jet atomization proceses; Liquid-propellant droplets dynamics and combustions in supercritical forced convective environments; Contributions of shear coaxial injectors to liquid rocket motor combustion instabilities; High pressure combustion studies under combustion driven oscillatory flow conditions; Droplet collision on liquid propellant combustion; Combustion and plumes; Development of a collisional radiative emission model for strongly nonequilibrium flows; Energy transfer processes in the production of excited states in reacting rocket flows; modeling nonequilibrium radiation in high altitude plumes; kinetics of plume radiation, and of HEDMs and metallic fuels combustion; Nonsteady combustion mechanisms of advanced solid propellants; Chemical mechanisms at the burning surface. p15