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...

This study discusses the design of a new experimental platform, the Hybrid Flame Analyzer (HFA) to measure burning velocity of gas, dust, and hybrid (gas and dust) premixed flames. The HFA is used to analyze a particle–gas–air system of coal dust particles (75–90 lm and 106–120 lm) in a premixed CH4–air (/g = 0.8, 1.0 and 1.2) flame. Experimental results show that particles usually increase the...

Fully developed stationary premixed flames are obtained by DNS in an incoming homogeneous isotropic turbulent flow. Analysis based on the Favre-averaged transport equation of turbulent kinetic energy shows that pressure gradient term and pressure work term increase turbulent kinetic energy in the flame region, and these terms produce anisotropic turbulence. The counter-gradient diffusion domina...

High-speed planar laser-induced fluorescence (PLIF) and 3-D large eddy simulations (LES) are used to study turbulent flame kernel growth, wrinkling and the formation of separated flame pockets in methane/air mixtures. Turbulence was effected by a set of rotary fans situated in a cylindrical enclosure. Flame wrinkling was followed on sequential 2-D OH images captured at kHz repetition rates. Und...

Flame instabilities play a dominant role in accelerating the burning front to a large fraction of the speed of sound in a Type Ia supernova. We present a threedimensional numerical simulation of a Rayleigh-Taylor unstable carbon flame, following its evolution through the transition to turbulence. A low Mach number hydrodynamics method is used, freeing us from the harsh timestep restrictions imp...

Changes in flow strain and mixture composition on the order of a flame time scale are characteristic of many practical combustion processes. Accurately predicting the unsteady reponse of burning to these changes requires detailed modeling of species transport and chemical kinetics. This thesis formulates a detailed one-dimensional computational model for arbitrary unsteady conditions of strain ...

Microscopic turbulence-flame interactions of thermonuclear fusion flames occuring in Type Ia Supernovae were studied by means of incompressible direct numerical simulations with a highly simplified flame description. The flame is treated as a single diffusive scalar field with a nonlinear source term. It is characterized by its Prandtl number, Pr ≪ 1, and laminar flame speed, SL. We find that i...

In recent years, Large Eddy Simulation (LES) has been successfully applied to non-premixed and premixed turbulent combustion problems [1, 2, 3]. In most technical combustion applications, the pure non-premixed or premixed combustion models are no longer valid, since partially premixed combustion has to be taken into account. An example is the stabilization region of a lifted non-premixed flame....

In this paper, we present a detailed experimental study of turbulence chemistry interactions in the ‘‘DLR_B’’ turbulent jet diffusion flame. The flame operates on mixtures of CH4, H2, and N2 in the fuel stream at Re = 22,800 and is a target flame within the TNF workshop. Extinction and re-ignition events can be tracked in real time and related to the underlying flow field phenomena and temperat...

It is known that unconfined dust explosions typically start off with a relatively weak primary flame followed by a severe secondary explosion. We show that clustering of dust particles in a temperature stratified turbulent flow ahead of the primary flame may give rise to a significant increase in the radiation penetration length. These particle clusters, even far ahead of the flame, are suffici...