An investigation is carried out into the ranges of Damköhler number and Lewis number, less than unity, in which different forms of combustion phenomena arise within a non-premixed counterflow; cases that are symmetrical across the counterflow are chosen for study. These link oscillatory and steady propagation of flame edges, zero propagation speeds, isolated flame tubes, quenching and marginal ...

The objectives of the present study are the formulation of the models of flame front evolution capturing the effects of flame propagation in the prescribed non-stationary premixed gas flow field. The algorithm of real time simulations of flame evolution within frame of “flamelet” approach is offered to model shape of flame front propagating in the given non stationary gas flow fields. The algor...

The characteristics of triple flames in a hydrogen–air mixing layer are studied using direct numerical simulation with detailed chemistry. Triple flames are initiated by imposing a temperature ignition source in the center of a scalar mixing layer of nonuniform thickness, thereby forming a pair of freely propagating triple flames. Two different fuel streams are studied: pure hydrogen and hydrog...

This paper reports on an experimental study of the influence of a nanosecond repetitively pulsed spark discharge on the stability domain of a propane/air flame. This flame is produced in a lean premixed swirled combustor representative of an aeronautical combustion chamber. The lean extinction limits of the flame produced without and with plasma are determined and compared. It appears that only...

One strategy for reducing US dependence on petroleum is to develop new combustion technologies for burning the fuel-lean mixtures of hydrogen or hydrogen-rich syngas fuels obtained from the gasification of coal and biomass. Fuel-flexible combustion systems based on lean premixed combustion have the potential for dramatically reducing pollutant emissions in transportation systems, heat and stati...

The unresolved Q-branch profiles in the Raman spectra of' nitrogen in premixed, laminar, methane-air, propane-air and butane-air flames with lean to stoichiometric fuel-air equivalence ratios have been recorded experimentally and used to determine flame temperature s with a precision of about 10f0using an iterative computer program which fitted calculated nitrogen spectra to the experimentally ...

Fellowship Experience Throughout my twelve-week fellowship at Pratt & Whitney I had the opportunity to interact with numerous engineers and managers as well as to be exposed to a variety of disciplines and areas of engineering. My mentor, Bill Proscia, is an expert in the field of combustion instability analysis and modeling. I gained valuable experience working on a combustion project under hi...

A new model for turbulent flame velocity of premixed flame in spark ignition engine for Iso-octane air mixture has been developed and validated for a wide range of engine operating parameters. The model developed is a zero dimensional thermodynamic model. The effects of engine speed (600-1160 rpm), equivalence ratio (0.7-1.1), unburnt mixture temperature (532650 Rankine), compression ratio (5-8...

The interaction of a premixed methane/air flame with a counter-rotating vortex pair is analyzed using a parallel low-Mach-number computational model that is based on a detailed C1C2 chemical mechanism. Attention is focused on the transient response of the heat release rate and the flame structure at the centerline of the vortex pair. Results are obtained for vortex pairs of different strengths ...

This paper presents an experimental study on the dynamics of a ducted, conical, laminar premixed flame subjected to low amplitude acoustic excitation from upstream. The heat release response of the flame to velocity disturbances is investigated through measurement of the so called ‘flame transfer function’ for a wide range of forcing frequencies. The results are compared with those predicted by...