Simulations of forced ignition of non-premixed laminar counterflow flames are used to study the effect of strain rate on ignition success. A one dimensional calculation is performed, using detailed methane chemical kinetics and treating the spark as an instantaneous heat release in an inert mixing layer. Ignition success depends on the mixture composition at the spark location, resulting in lea...

As an attempt at providing insight to develop better modeling strategies for HCCI engines, the ignition and propagation of a reaction front in a premixed fuel/air stream mixed with hotter exhaust gases is computationally investigated using the opposed-flow configuration. The effects of heat and radical transport are studied by imposing various mixing rates on the system. The results show that t...

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 cur...

The ignition of a laminar non-premixed H2/air mixing layer with an embedded vortex was computationally studied with detailed chemistry and transport. The initial vortex velocity and pressure fields were specified based on the stream function of an incompressible nonviscous vortex. The fuel side is pure hydrogen at 300 K, and the oxidizer side is air at 2000 K. The vortex evolution process was f...

This paper presents a computational algorithm to predict highly-transient ame behavior in counter ow situations. The rst objective of the paper is to extend the transient counter ow problem to incorporate some gasdynamic compressibility e ects, yet retain the desirable similarity structure. By relaxing assumptions in earlier formulations, the computational algorithms can deliver high accuracy e...

The research presented here describes the numerical optimization of a multi-step ignition model to predict the auto-ignition of dimethyl ether (DME) in a rapid compression machine. The multi-step modeling concept is aimed at capturing the ignition behavior of new oxygenated fuel blends, where detailed or reducedmechanisms are not available. Experimental data for the ignition ofDME/O2/N2mixtures...

Experiments have been carried out to measure the spark ignition energy of Jet A vapor in air. A range of ignition energies from 1 mJ to 100 J was examined in these tests. The test method was validated by first measuring ignition energies for lean mixtures of the fuels hexane (C6H6) and propane (C3H8) in air at normal temperature (295 K) and pressure (1 atm). These results agree with existing da...

A well-defined plasma assisted combustion system with novel in situ discharge in a counterflow diffusion flame was developed to study the direct coupling kinetic effect of non-equilibrium plasma on flame ignition and extinction. A uniform discharge was generated between the burner nozzles by placing porous metal electrodes at the nozzle exits. The ignition and extinction characteristics of CH4/...

To realize large-percentage biomass co-firing with coal in existing coal-fired boilers, the combustion behavior of biomass is expected to be similar or comparable to that of coal. When co-firing with coal, biomass is not necessarily to be ground as fine as the dedicated coal particles, because of its higher reactivity. With the objective of achieving promising performance of co-firing with dedi...