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DISSERTATION RESEARCH--

TOPIC

CORRELATION OF IGNITION DELAY WITH FUEL COMPOSITION AND STATE FOR 

APPLICATION TO GAS TURBINE COMBUSTION

        Lean premixed combustion technology is widely accepted in gas turbine industry to reduce pollutant emissions. Engines which use this strategy are being installed world-wide. In the lean-premix combustors and other types of low-emissions combustors, fuel and air are premixed before combustion. One of the most important concerns is the ignition delay phenomenon in these systems. We have to avoid auto-ignition at all costs in these systems to protect the combustor components as well as to avoid producing unacceptably high levels of pollutant emissions. So, it is very important to understand ignition delay times in lean premixed combustion systems.

        In this dissertation, ignition delay times are studied for different fuels such as natural gas fuels, medium BTU fuels and low BTU fuels under different conditions. The effects of temperature, pressure, equivalent ratio, fuel composition and state, and turbulence intensity on ignition delay times are addressed by using experimental and modeling methods. The experimental method is a continuous flow device with a 147-inch-long test section. A series of photodiodes and thermocouples are used as ignition detectors. Modeling methods include chemical kinetics modeling, CFD modeling and statistical optimization. The testing pressures vary from one atmosphere to fifteen atmospheres and temperature can go up to 1200 ° F. If possible, liquid fuels can also be tested in this research.

        The goal of this dissertation research is to establish the understanding of autoignition in lean premixed combustion systems as a function of fuel composition for various inlet temperature, pressure, turbulence intensities, and fuel concentrations. This research will:

• Directly apply to challenges facing advanced gas turbine applications;
• Provide insight into the nature of auto-ignition delay in lean, premixed combustion systems by judicious experimental and theoretical analyses;
• Provide needed data as an archive for future research.

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