Characterization of Turbulent Combustion using Advanced Laser Diagnostics

Turbulent combustion takes place in nearly all combustion-related applications, including gas turbines, boilers, furnaces, engines, explosions and fires. A thorough understanding of the basic phenomena of turbulent combustion is essential to develop advanced combustion technologies to achieve low exhaust emissions and high energy efficiency. Premixed turbulent combustion attracts the most attention from experimentalists, modellers, and theoreticians, due to a complex turbulence-chemistry interaction. This strong interaction brings the greatest challenge to measure a turbulent burning velocity that is defined as the gas velocity into the flame front. This project seeks to accurately characterize the premixed turbulent flame by measuring the burning velocity and the flame structure using spatially (x-, y-, z-) and temporally (t) resolved 4D laser analysis.

For the above purposes, this project involves developing advance laser diagnostics, e.g. particle image velocimetry PIV, as a practical way of characterising gaseous turbulence. It involves seeding the gas with small particles of olive oil in an aerosol of very limited concentration and a laser beam is formed into a light sheet illuminating seeding particles. The scattered light is recorded using a high speed and high resolution digital camera for extracting the velocity field. Meanwhile, swinging laser sheets will be incorporated to obtain the three-dimensional turbulent flame structure which allows quantitatively characterization on flame surface area, burned gas volume, reaction progress variable and flame surface density. The outcome of the research will be a unique technique of high speed photography of explosive flame propagation. This will greatly enhance the understanding of premixed turbulent flame, as well as characterize the turbulent burning velocity of newly developed fuels and ensure their successful application in the context of the global energy transition.