The effects of spectral radiation absorption on the flame speed at normal and elevated pressures were experimentally and numerically investigated using the CO2 diluted outwardly propagating CH4-O2-He flames. Experimentally, the laminar burning velocities of CH4-O2-HeCO2 mixtures at both normal and elevated pressures (up to 5 atm) were measured by using a pressure-release type spherical bomb. Th...

We study a thermo-diffusive combustion model for premixed flames propagating in reactive gaseous mixtures which contain inert dust. As observed by Joulin, radiative transfer of heat may significantly enhance the flame temperature and its propagation speed. The Joulin effect is at its most pronounced in the parameter regime where the medium is very transparent while radiative flux dominates conv...

One of the effective ways to enhance flame retardance of polyacrylonitrile (PAN) is through a reactive route, primarily developed in our laboratories, which involved chemical modification reactions utilising phosphorus-containing comonomers. In the present study, diethyl(acryloyloxymethyl)phosphonate (DEAMP) and diethyl(1-acryloyloxyethyl)phosphonate (DE1AEP) were synthesised and copolymerised ...

The purpose of this paper is to address the differences observed in the oxidative kinetics between flame and diesel derived soots. In particular, it has been observed that flame soot has a significantly higher activation energy for oxidation than does diesel soot. The hypothesis tested in this paper is that metals, possibly coming from lubricating oils, within diesel generated soot particles ma...

The effects of fuel and air stream dilution (ASD) with carbon dioxide on the suppression of normal and microgravity laminar methane–air partially premixed coflow jet flames were experimentally and numerically investigated. Experiments were conducted both in our normal-gravity laboratory and at the NASA Glenn Research Center 2.2 s drop tower. Measurements included flame topology and liftoff heig...

The problem of flame propagation in imperfectly premixed mixtures—mixtures of reactants with variable composition—is considered in this numerical study. We carry out two-dimensional direct numerical simulations of a flame propagating in a globally lean fuel-oxidizer mixture with imposed velocity and composition fluctuations of various intensities. The configuration adopted is that of a flame fr...

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-...

The effect of inlet swirl on the flow development and combustion dynamics in a lean-premixed swirl-stabilized combustor has been numerically investigated using a large-eddy-simulation (LES) technique along with a level-set flamelet library approach. Results indicate that when the inlet swirl number exceeds a critical value, a vortex-breakdown-induced central toroidal recirculation zone is estab...

The purpose of this study was to compare the effect of casting temperature and atmosphere on the castability of three Ni-Cr alloys against direct flame casting method. Vera Bond (VB), Vera Bond 2 (VB2) and Wiron 99 (W99) were cast at three temperatures: VB and VB2 (1310 °C, 1340 °C and 1370 °C); W99 (1400 °C, 1430 °C and 1460 °C) in atmosphere, vacuum and direct flame. Each alloy was cast in se...

The interaction of a vortex pair with a premixed flame serves as an important prototype for premixed turbulent combustion. In this study, we investigate the interaction of a counterrotating vortex pair with an initially flat premixed methane flame. We focus on characterizing the mechanical nature of the flame-vortex interaction and on the features of the interaction strongly affected by fuel eq...