Showing papers in "Combustion and Flame in 1999"

TL;DR: In this article, a simple atom-equivalent method was used to predict gas, liquid, and solid heats of formation of energetic molecules, and the results showed that the calculated gas-phase heat of formation had a root mean square (rms) deviation of 3.1 kcal/mol and a maximum deviation of 7.3 kcal/m from 35 experimental values.

TL;DR: In this paper, a detailed soot growth model was developed for an axisymmetric, laminar, coflow diffusion flame, in which the equations for particle production have been coupled to the flow and gaseous species conservation equations.

TL;DR: In this paper, a model of jet diffusion flames, burning methane at atmospheric and elevated pressure, is presented and the main emphasis is on the intimate coupling between the soot production rate and the flame radiative heat loss.

TL;DR: In this paper, two-dimensional reactive Navier-Stokes equations for an acetylene-air mixture are solved numerically to simulate the interaction of a shock wave and an expanding flame front, the formation of a flame brush, and deflagration-to-detonation transition.

TL;DR: In this article, generalized expressions for the flame response to weak stretch rate variations were derived based on an integral analysis, which yielded the laminar flame speeds through linear extrapolation to zero stretch rate.

TL;DR: In this article, an analytical study was conducted to supplement recent high-pressure shock tube measurements of CH 4 /O 2 ignition at elevated pressures (40-260 atm), low dilution levels (fuel plus oxidizer ≥ 30%), intermediate temperatures (1040-1500 K), and equivalence ratios as high as 6.

TL;DR: In this paper, a laser-induced spark ignition of CH{sub 4}-air mixtures was experimentally investigated using a nanosecond pulse at 1,064 nm from a Q-switched Nd-Yag laser.

TL;DR: In this paper, a detailed chemical kinetic model consisting of 469 reactions and 71 species was used to describe the high-temperature kinetics of propene, propyne, allene, and propane.

TL;DR: In this article, the results of numerical simulations of cellular detonations generated by using numerical noise as a source of initial fluctuations imposed on a strong planar shock propagating through the reactive medium are reported.

TL;DR: In this article, an algorithm for the construction of global reduced mechanisms, based on concepts from the Computational Singular Perturbation method, was presented for a laminar premixed CH4/Air flame and a complex detailed chemical kinetics mechanism.

TL;DR: In this article, the authors identify the contributions of curvature to the displacement speed by using the governing transport equation for the deficient reactant, and they show that displacement speed is a balance of three components: reaction, normal diffusion, and curvature.

TL;DR: In this article, a kinetic model describing the growth of polycyclic aromatic hydrocarbons (PAH) up to coronene (C24H12) and of C60 and C70 fullerenes is developed.

TL;DR: In this paper, a two-stage counterflow methane-air flames at normal atmospheric pressure and a feed-stream temperature of about 300 K were measured and computations were made of structures of two stage counter-flow methane air flames, including formation of species containing two carbon atoms.

TL;DR: In this paper, the authors studied the characteristics of triple flames in a hydrogen-air mixing layer using direct numerical simulation with detailed chemistry and found that the triple point, defined as the location of maximum heat release, is always in the proximity of the stoichiometric mixture fraction line.

TL;DR: In this article, the authors investigated the characteristics of propagating tribrachial flames in non-premixed laminar jets and found that the edge of the propagating flame has a tribarachial flame structure.

TL;DR: In this article, the authors used a flame model for coupled thermal radiation and soot production in a laboratory-scale rig, where the flame properties needed for model validation were measured at 1 and 3 atm.

TL;DR: In this article, the results of an experimental study of the combustion of single aluminum particles in N2/O2 and pure O2 gas mixtures were presented and interpreted, and the relationship between aluminum particle combustion behavior and particle internal and surface structure and composition was illustrated.

TL;DR: In this paper, the first direct comparison between primary particle sizes based on optical measurements and those directly measured through transmission electron microscopy (TEM) is presented. But the results are limited to a single wavelength.

TL;DR: In this article, a particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) investigation of a lifted jet diffusion flame was performed.

TL;DR: In this paper, the authors describe numerical simulations of deflagration-to-detonation transition (DDT) for conditions similar to reflected shock-tube experiments in an acetylene-air mixture (100 Torr, 298 K).

TL;DR: In this paper, a laminar flamelet description is derived for premixed laminara flames and the full set of 3D instationary combustion equations is decomposed in three parts: (1) a flow and mixing system without chemical reactions, described by the momentum, enthalpy, and element conservation equations, (2) the G-equation for the flame motion, and (3) a flamelet system describing the inner flame structure and the local mass burning rate.

TL;DR: In this article, a growth mechanism of polycyclic aromatic hydrocarbons (PAH+s) and the transition to small charged soot particles was discussed, which is very probably also valid for uncharged PAHs.

TL;DR: In this article, joint velocity/scalar imaging measurements are performed in turbulent premixed natural-gas/air flames to better characterize the turbulent flux of mean reaction progress variable, ρu″c″.

TL;DR: In this article, a laminar gas jet diffusion flames were measured for burning, methane, ethane, and propane in quiescentral air, and the normalized lengths of both buoyant and non-buoyant flames were proportional to the source Reynolds number.

TL;DR: In this article, the authors investigate the low-velocity filtration combustion reaction of lean methane/air mixtures flowing through a packed bed and compare to experimental results, showing that the computed wave speeds show the same trends as the theoretical predictions but are generally higher.

TL;DR: In this article, the authors compared the Probability Density Function (PDF) method and the Conditional Moment Closure (CMC) method using the same turbulence model, radiation model, reduced chemical mechanism, and boundary conditions, so that similarities and differences between these two approaches for the coupling of turbulence and chemistry may be isolated and fully understood.

TL;DR: In this article, an experimental and theoretical study of premixed flame propagation in a number of small-scale, cylindrical vessels is described, which provides further understanding of flame propagation and the generation of overpressure in explosions, and allows the assessment of a mathematical model of explosions through comparisons with the experimental data obtained.

TL;DR: In this paper, a gas-phase inhibition mechanism involving catalytic removal of H atoms by iron-containing species is presented for premixed and counterflow diffusion flames of methane, oxygen, and nitrogen.

TL;DR: In this paper, the interaction of a shock wave and a sinusoidally perturbed premixed flame was studied by solving the reactive Navier-Stokes equations with flame front resolved, and an idealized chemical model was used that reproduces the combustion properties of a stoichiometric acetylene-air mixture.

TL;DR: In this paper, a two-dimensional elliptic fluid mechanical model was used, which included elementary reactions for both gaseous and surface chemistry, to investigate the catalytically stabilized combustion (CST) of a lean (equivalence ratio Φ = 0.4) methane-air mixture.