Active control of thermoacoustic instabilities in continuous premixed combustion processes is being increasingly investigated for operating at lean low NOX conditions. Recently, we have developed a model-based approach for active control design which accounts for the underlying acoustics, heat release dynamics, and sensor and actuator dynamics. While this model captures a number of the dominant...

One of the well-known properties of turbulent, premixed flames is that their speed of propagtion is correlated to the intensity of the turbulence they encounter. A simple consequence is that these types of flames are inherently unstable. Given a source of turbulence, if the flame is propagating faster than the mean flow, it will drift upstream and encounter increased turbulent intensities that ...

The dissipation rate of a scalar variance is related to the mean heat release in turbulent combustion. Mixture fraction interest for non-premixed combustion, and reaction progress variable relevant premixed A great deal work conducted past studies understand spectra passive transport flows. very brief summary these bring out salient characteristics spectrum given first. Then, classical analysis...

Aromatics growth beyond 2-, 3-ring PAH is analyzed through a radical-molecule reaction mechanism which, in combination with a previously developed PAH model, is able to predict the size distribution of aromatic structures formed in rich premixed flames of ethylene at atmospheric pressure with C/O ratios across the soot threshold limit. Modeling results are in good agreement with experimental da...

Flame–turbulence interactions are at the heart of modern combustion research as they have a major influence on efficiency, stability of operation and pollutant emissions. The problem remains a formidable challenge, and predictive modelling and the implementation of active control measures both rely on further fundamental measurements. Model burners with simple geometry offer an opportunity for ...

The relative importance of formation pathways for benzene, an important precursor to soot formation, was determined from the simulation of 22 premixed flames for a wide range of equivalence ratios (1.0– 3.06), fuels (C1–C12), and pressures (20–760 torr). The maximum benzene concentrations in 15 out of these flames were well reproduced within 30% of the experimental data. Fuel structural propert...

Laminar burning velocities and flammability limits of premixed methane/air flames in the presence of various inert gases including helium, argon, nitrogen and carbon dioxide were investigated by combined use of microgravity experiments and computations. The experiments used a short-drop free-fall laboratory facility that can eliminate the effect of buoyancy on flames and therefore enable accura...

Turbulence is a supermixer. Turbulent mixing has immense consequences for physical phenomena spanning astrophysical to atomistic scales under both high- and low-energy-density conditions. It influences thermonuclear fusion in inertial and magnetic confinement systems; governs dynamics of supernovae, accretion disks and explosions; dominates stellar convection, planetary interiors and mantle-lit...

Gas motion within the cylinder is one of the major factors that control the combustion process in spark ignition engine. It also has significant impact on heat transfer. Both the bulk gas motion and the turbulence characteristics of the flow are important and governing the overall behavior of the flow. An arrangement for obtaining a stratified charge, using port injection, is proposed for a ...