Jet Flame Stability Research at NCSU
April 1, 2005
By Dr. N. Ma, NCSU

Dr. Kevin Lyons

Hydrocarbon combustion is an important element of many power and energy conversion schemes. Its implications are critical to transportation, propulsion, the power industry as well as residential and commercial heating. Turbulent jet flames are an important part of many practical industrial combustion devices, with applications ranging from small boilers and water heaters to large gas turbines. While laboratory jet flames contain some of the elements inherent in industrial-scale combustors, their relative simplicity makes them ideal for joint experimental and theoretical research.

Professor Lyons' group's research is aimed at understanding fundamental aspects of combustion in these types of systems. Specifically, experimental research is employed to understand the reaction zone structure in jet flames as well as spray flames. The conditions under which the reaction zone extinguishes, propagates and changes morphology are of interest. Professor Lyons' graduate students have investigated the following issues in jet flames: the effects of air co-flow on spray flame structure (see figure of a lifted jet spray flame with multiple reaction zones), the effects of fuel dilution on flame structure , liftoff and blowout. These studies are pursued with an eye toward discovering new phenomena in reacting jets as well as for physical model validation and development. The overall goal is to develop a coherent physical picture of flame structure and stability, incorporating the pertinent fluid physics, flame chemistry and heat release.

In addition to research by Lyons and his students, related combustion research is ongoing in other groups. Professor Roberts and his students investigate soot formation and engine flame kernel research, both with and without high pressure effects. These experiments are of interest since the elements of high pressure and flame geometry yield results crucial to engine designers. Professor Echekki and his students employ numerical modeling to understand similar combustion systems. These “numerical experiments” are aimed at developing predictive models of combustion systems like engine flame kernels and combustion zones around and in jets. Additionally, this work benefits from Professor Edwards' research in computational fluid dynamics and combustion. All of this research is in place due to the strong commitment of the MAE department in establishing a research concentration in fundamental combustion science. Future directions of the program are to expand into applications concerning I. C. engine research, gas turbine combustion research and fuel cell research.