A dominant factor in determining the burning rate of a premixed turbulent flame is the degree to which the flame front is wrinkled by turbulence. Higher turbulent intensities lead to greater wrinkling of the flame front and an increase in the turbulent burning rate. This picture of turbulent flame dynamics must be modified, however, to accommodate the affects of variations in the local propagat...

In this paper, a one dimensional premixed laminar methane flame is subjected to acoustic oscillations and studied. The purpose of this analysis is to investigate the effects of acoustic perturbations on the reaction rates of different species, with a view to their respective contribution to thermoacoustic instabilities. Acoustically transparent non reflecting boundary conditions are employed. T...

A computational study is performed to investigate the effects of hydrogen addition on the fundamental characteristics of stretched methane/air premixed flame in an opposed flow configuration. The problem is of interest as a potential application to gas turbines and spark-ignition engines, where it has been anticipated that addition of a small amount of hydrogen will extend the lean flammability...

In this paper, the implication of various grades of hydrogen rich gas on the in-cylinder flame speed, and on the knock propensity, are discussed. The laminar flame propagation speed of methane with various grades of hydrogen-rich gas addition has been calculated. The effect of adding hydrogen, hydrogen rich gas from an ideal reformer (synthesis gas), as well as that from a non-catalytic plasmat...

Minimum ignition energies and flame radii as a function of time were measured for near-limit, limit, and sublimit fuel-lean methane-air mixtures burning at one-g and zero-g. Minimum ignition energy values were the same at one-g and zero-g except for mixtures very near the zero-g flammability limit and leaner, where the zero-g values were much higher than the one-g values. For sublimit mixtures ...

We present three-dimensional, time-dependent simulations of the flowfield of a laboratory-scale slot burner. The simulations are performed using an adaptive time-dependent low Mach number combustion algorithm based on a second-order projection formulation that conserves both species mass and total enthalpy. The methodology incorporates detailed chemical kinetics and a mixture model for differen...

Flame acceleration and deflagration-to-detonation transitions (DDT) in large obstructed channels filled with a stoichiometric methane–air mixture are simulated using a single-step reaction mechanism. The reaction parameters are calibrated using known velocities and length scales of laminar flames and detonations. Calculations of the flame dynamics and DDT in channels with obstacles are compared...

The gaseous by-product from natural or industrial processes which contain a small concentration of combustible gases is called a low-grade fuel or low calorific value gases (LCVG). Identifying the best strategy for efficient burning of such gases, where there is a bulk production, becomes inevitable to improve the efficiency of a system and reduction of pollutants emission. LCVGs have calorific...

The characteristics of lifted laminar triple flames in the near field of the burner exit are experimentally and numerically investigated. The flames are established by introducing a nitrogen-diluted rich mixture of methane and air from an inner tube and a lean mixture from a concentric outer tube. The temperature and major species concentrations are measured using thermocouples and gas chromato...

Edge flames were investigated in a methane/O2/N2 counterflow diffusion flame burner. In a typical experiment, a stable counterflow diffusion flame in an axysymmetric configuration was perturbed by lowering the relevant Damköhler number slightly below the extinction value, Daext. As a result, the flame extinguished in the vicinity of the burner axis where conditions were uniform. An edge flame e...