3D heat release oscillation field measured using chemiluminescence tomography

Thermoacoustic Instabilities

Thermoacoustic instabilities can occur in any enclosed combustion system, but are particularly problematic in lean premixed gas turbine combustors and rocket engines. These instabilities result in high amplitude pressure and heat release rate oscillations that can reduce efficiency and cause structural damage to the engine.

The Experimental Engines Lab has several ongoing projects in the area of thermoacoustics. Our particular focus is on understanding the detailed flow-flame-acoustic coupling mechanisms, in order to design such coupling out of the system. This negates the need for complex, expensive, heavy, and unreliable control systems.

We currently are working with aircraft engine companies to measure thermoacoustic coupling inside flight-relevant hardware using the lab's laser and optical measurement techniques. The resultant data is being analyzed to determine not only the steady-state coupling mechanisms, but also those associated with non-stationary behavior, e.g. triggering of changes in oscillation amplitude. Furthermore, our analysis is being compared to advanced simulations of these combustors, in order to determine if the simulations can predict the underlying physics.