In this paper, the effect of air turbulence intensity on the flame structure in various radii and lengths of a flame holder numerically studied. Finite volume method is used to solve the governing equations. The obtained numerical results using realizable k-ε and β-PDF models show a good agreement with the experimental data. The results show that flame holder with greater lengths yield shorter ...

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...

An overview of commercially used flame retardants is give. The most used flame retardants are illustrated and the seven major markets, which use 96% of all flame-retarded polymers, are described. Annual flame retardant growth rate for each major market is also projected. Toxicity data are reviewed on only those compositions that are considered commercially significant today. This includes 18 co...

For purposes of this short communication, sonographic (ultrasound) techniques that utilize microbubbles (MB) is referred to as microbubble sonography (MBS). MBS has important diagnostic and therapeutic (thus the term "theranostic") clinical applications in targeted or “personalized” oncology. For diagnosis, MBS provides detailed depiction of tumor microvascularity and a means to monitor its res...

The effects of H2 enrichment on the propagation of laminar CH4–air triple flames in axisymmetric coflowing jets are numerically investigated. A comprehensive, time-dependent computational model, which employs a detailed description of chemistry and transport, is used to simulate the transient ignition and flame propagation phenomena. Flames are ignited in a jet-mixing layer far downstream of th...

In gas explosions, the unsteady coupling of the propagating flame and the flow field induced by the presence of blockages along the flame path produces vortices of different scales ahead of the flame front. The resulting flame/vortex interaction intensifies the rate of flame propagation and the pressure rise. In this paper, a joint numerical and experimental study of unsteady premixed flame pro...

Combustion instability is a process which involves unsteady chemical kinetic, fluid mechanic, and acoustic processes. It can lead to unstable behavior and be detrimental in ways ranging from faster part fatigue to catastrophic system failure. In terms of combustion methodology, combustion instability has been a key issue for lean premixed combustion. The primary objective of this work is to imp...

This work focuses upon the effects of DC electric fields on the stability of downward propagating atmospheric pressure premixed propane–air flames under experimental conditions that provide close coupling of the electric field to the flame. With the appropriate electrode geometry, modest applied voltages are shown to drive a stable conical flame first into a wrinkled-laminar flamelet geometry, ...