We report the use of a tunable ArF laser at 193.26 nm to record simultaneous single-laser-shot, planar images of molecular hydrogen and hot oxygen in a turbulent H(2)-air diffusion flame. Excitation spectra of fuel and oxidantrich flame zones confirm a partial overlap of the two-photon H(2) (6,0) Q(1) E, F ? X and single-photon O(2) (10,2) R(17) B ? X (Schumann-Runge) absorption bands. UV Rayle...

A modified version of the linear eddy model (LEM) for subgrid combustion is developed and used for studying the properties of turbulent premixed flames in the core region of Couette flow. The handling of the burning (diffusion/reaction) and specie transport, in this new approach, is fully deterministic. The model is, therefore, found to predict the correct laminar flame speed in the limit of ze...

Soot concentration distribution is investigated both numerically and experimentally in methane-air diffusion flame. The experimental work is conducted with a cylindrical swirl stabilized combustor. Filter paper technique is used to measure soot volume fraction inside the combustor. The numerical simulation is based on the solution of the fully-coupled conservation equations for swirling turbule...

Imaging scheme based on Acetone-OH simultaneous PLIF (Planer Laser-Induced Fluorescence) is applied for diagnostics of reactive zone over the premixed flames and the reactive zone imaging are demonstrated for turbulent premixed flame conditions. In the present study, visualization of reactive zone is brought by simultaneous measurement of unburned zone through acetone (seeded into the fuel flow...

Large eddy simulations (LES), where the large-scale motions are explicitly computed, is a promising tool for numerical simulations of reactive flows which generally exhibit large coherent structures. Nevertheless, subgrid-scale models have to be developed to describe the effects of the smaller flow motions not resolved in the simulation. An experimental method is presented for validation and de...

Three-dimensional direct numerical simulation of lean premixed hydrogen flames is used to explore the influence of species and thermal diffusion and viscosity on the flame structure and turbulent flame response. The leadingorder flame response is shown to be due to the global Lewis number with little influence from the other species. The previously-reported observation of decorrelation of fuel ...

The acoustic power of an oscillating flame is measured. A turbulent premixed propane/air flame is situated near a pressure antinode of a standing wave in a laboratory combustion chamber. This standing wave is generated by a piston. The fluctuating heat release of the flame will supply acoustic power to the standing wave as postulated by Rayleigh. This flame acoustic power is obtained by setting...

Mesoscale internal combustion engines for a variety of new combustion system applications have dimensions that are far smaller than conventional macroscale engines, yet unlike true microscale engines allow significant mean flow and turbulence to be created in the combustion chamber by the injection process. The resulting flow allows minimization of the combustion time by augmenting flame propag...

This research started on May, 1999 at the committee of turbulent combustion in the Open and Integrated Research Program (OIRP), The Science and Technology Agency (STA). The purpose of the research is to pursue a possibility on smart control of turbulent combustion and to achieve the improvement of combustion efficiency, that on environment and so on. The present feasibility study shows the foll...

In previous studies, we examined turbulence-flame interactions in carbonburning thermonuclear flames in Type Ia supernovae. In this study, we consider turbulence-flame interactions in the trailing oxygen flames. The two aims of the paper are to examine the response of the inductive oxygen flame to intense levels of turbulence, and to explore the possibility of transition to detonation in the ox...