A swirling CH4/air diffusion flame at atmospheric pressure was stabilized in a gas turbine model combustor with good optical access. The investigated flame with a thermal power of 10 kW and an overall equivalence ratio of 0.75 exhibited pronounced thermoacoustic oscillations at a frequency of 295 Hz. The main goal of the presented work was a detailed experimental characterization of the flame b...

This paper examines the use of plasma discharges in flame stabilization. Three different types of plasma discharges are applied to a lifted jet diffusion flame in a coflow configuration, and evaluated for their abilities to enhance flame stabilization. A single electrode corona discharge (SECD) between a platinum electrode and the flame base is found to maintain the flame at a 20% higher coflow...

In this study a procedure for sample digestion based on sample combustion assisted by microwave radiation is proposed. Combustion is started by microwave radiation in the presence of oxygen under pressure using ammonium nitrate as aid for ignition. The system was adapted in a microwave oven with quartz closed vessels. A quartz piece is used simultaneously as a sample holder and as protection to...

Editorial The statement is signed by the individual scientists and other professionals listed separately below. Please note that the views expressed are those of the authors and signatories; institutional affili­ ations are provided for identification purposes only. Abbreviations and an Annotated Statement are available as Supplemental Material (doi:10.1289/ehp.1003089). We, scientists from a v...

An experimental and numerical study was performed on the interaction of combustible solid particles with atmospheric, strained, laminar premixed methane/air and propane/air flames in normal gravity. The study was conducted in the opposed-jet configuration in which a single flame was stabilized below the gas stagnation plane by counterflowing a mixture against an air jet. Into the flame were see...

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 ...

Title of Document: Upward Flame Spread Over Discrete Fuels Colin H. Miller, Master of Science, 2014 Directed By: Dr. Michael J. Gollner, Assistant Professor, Department of Fire Protection Engineering Upward flame spread over discrete fuels has been analyzed through experimental research on vertical arrays of alternating lengths of PMMA and insulation. By manipulating the lengths of the PMMA fue...

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...

We summarize our current research on combustion aerosols. First, sampling devices for the analyses of flame gases are described. The flame gas samples are investigated by mass spectroscopy and by standard aerosol techniques. Time-of-flight mass spectroscopy is well suited to study formation and growth of soot precursor molecules. Fullerenes can also be seen in some mass spectra of flame gases. ...

A turbulent lifted slot-jet flame is studied using direct numerical simulation (DNS). A single step chemistry model is employed with a mixture-fraction dependent activation energy to quantitatively reproduce the dependence of laminar burning rate on equivalence ratio that is typical of hydrocarbon fuels. It is observed that the leading flame edge exhibits a single branch close to the stoichiome...