58852 - Numerical Investigations of a High Pressure Compressor Exposed to Unsteady Pressure Gain Combustion Employing Data-Driven Methods 

The employment of pressure gain combustion (PGC) in gas turbines introduces additional unsteadiness to the inherently complex turbomachinery flow. A high pressure compressor, located right upstream of the PGC section, is therefore constantly exposed to outlet flow fluctuations, experiencing drop in efficiency, increase in pressure loss as well as higher stalling and structural failure risks.

This numerical work analyzes how one stage of a well-stablished engine, namely the NASA EEE core, reacts to the disturbances induced by the potential implementation of PGC. Unsteady computational fluid dynamics are employed with boundary conditions simulating the combustion unsteadiness. The main focus of the current paper is the application of data-driven methods, such as proper orthogonal decomposition and particularly dynamic mode decomposition, when comparing the high pressure compressor baseline operation with the PGC-disturbed case. Representative flow features and their frequency content, not identifiable with typical methods such as phase-averaging, are easily extracted from a sequence of snapshots. The results allow not only the identification of the most relevant coherent structures present in the unsteady flow, but also how they change in the presence of PGC. This contribution sheds light on how novel PGC technology can be integrated with turbomachinery components, identifying modifications in the main flow features with the use of advanced decomposition techniques.