Combustion Dynamics

Since the 90's, there have been increasingly stringent regulations on pollutants emitted out of gas turbines. These have led engine manufacturers to operate combustors with premixed fuel and air. This allows for temperature control of the combustion process and hence the concentration of emissions. One significant drawback of operation in the premixed mode though, is the dynamic behavior of these combustors.

Combustion dynamics includes the phenomenon of pressure oscillations in both, aircraft and land-based power generation engines. These lead to cracks and thermal hot-spots in different parts of the engine. Understanding and control of these oscillations are key to the reliable and robust operation of power-plants and propulsion systems.

The objectives of these efforts are to develop a fundamental understanding of combustion dynamics in cases when flames are stabilized by recirculating flows formed in the wake behind sudden expansions or in swirl stabilized flows. We are currently working with syngas at varying hydrogen &ndash carbon monoxide ratios, premixed with air over a range of equivalence ratios, inlet temperatures and Reynolds numbers. We are conducting experiments in both a planar combustor and a newly designed axisymmetric combustor. The insight gained from these experiments will be used to suggest different variations on the flame stabilizations environments aimed at passively stabilizing the flames.