Four-Dimensional Measurement of Thermoacoustic Oscillations

Lean combustion of fuels, i.e. combustion with excess air, is efficient and low in emissions. Unfortunately, this type of combustion is prone to thermoacoustic oscillations with all fuels, including sustainably produced alternative fuels for aviation. The field of thermoacoustics now describes processes in which fluctuations in the heat release lead to the propagation of sound waves, which can retroactively amplify these combustion instabilities. These self- reinforcing pressure fluctuations can become so severe that the combustion chamber is damaged or the flame extinguishes. Due to the interaction of various physical quantities, thermoacoustic processes are so complex that they can only be simulated with the assistance of high-performance computers. Thermoacoustic oscillations must first be examined both spatially and time-resolved in test rigs to validate these simulations. In cooperation with the Technische Universität Dresden, this project is now to prove that the combination of laser-optical measurement methods with artificial intelligence algorithms allows a complete spatial and temporal recording of these thermoacoustic oscillations even with a limited viewing angle always present in such test rigs. We expect that such a "four- dimensional" innovative element in studying thermoacoustic phenomena will lead to a paradigm shift in understanding this coupling of acoustics and flame dynamics.