Part-Time Teaching Assistant
Academic Division: Energy, Fluid Mechanics and Turbomachinery
I am a final year PhD student under the supervision of Professor Epaminondas Mastorakos. My research focuses on the investigation of the effect of thermoacoustic instabilities on flame dynamics in gas turbine engines. The PhD is part of the University Gas Turbine Partnership between the University of Cambridge and Rolls-Royce plc.
The need for a better control of the flame temperature and for a considerable reduction in emissions has driven the wide employment of lean combustion in gas turbines. Such flames are prone to present severe thermoacoustic instabilities. As a result, pressure fluctuations subject the surfaces of the combustion chamber to increased heat loads, ultimately leading to performance degradation and system failure. These deleterious effects of unsteady combustion were recognised early in the development of rocket engines, however, this issue is still mainly addressed through the costly and time-consuming approach of trial and error.
Motivated by the gap in the existing literature and the largely unexplored phenomenon due to the complex mechanism of generation of thermoacoustic instabilities, this research aims to examine the effect of a number of parameters including that of external flame forcing, burner geometry,mode of combustion (premixed, non-premixed and spray flames) and equivalence ratio in the generation of thermoacoustic oscillations. The experiments involve the use of combustion diagnostic techniques and mainly advanced flame imaging techniques (high-speed chemiluminescence and laser induced fluorescence). For the post-processing analysis, apart from the conventional methods, a multivariate statistical analysis (Proper Orthogonal Decomposition) is used.
The results of this project are expected to provide a deeper scientific understanding of the nature of flow-flame interactions and of the underlying mechanisms in a system undergoing thermoacoustic instabilities. The outcome of this research can be further employed for the development of more accurate computational models of combustion that will allow the design of a new generation of gas turbines with greatly reduced thermoacoustic oscillations.