With the onset of climate change it is crucial to eliminate emissions, particularly for aviation reliant on gas turbine combustion. Computational models aid combustor improvement, but experimental data needed for validation is difficult to obtain. Fortunately, laser diagnostics c
...
With the onset of climate change it is crucial to eliminate emissions, particularly for aviation reliant on gas turbine combustion. Computational models aid combustor improvement, but experimental data needed for validation is difficult to obtain. Fortunately, laser diagnostics can now achieve non-intrusive, high-resolution combustion measurements, especially with hybrid femtosecond/picosecond (fs/ps) coherent Raman scattering (CRS). In this thesis, the goal was to develop hybrid fs/ps CRS spectroscopy for the CH4 ν2 vibrational mode. Methane merits investigation as a climate forcer alongside potential use in carbon-neutral hydrogen production. Time-resolved CRS was performed for collision-independent, collisional dephasing, and laminar CH4-air flame measurements. A time-domain model well-reproduced experiments, along with extracting molecule-specific ν2 Q-branch dephasing linewidth parameters. Additionally, fundamental physio-chemical processes were observed in a spectral molecular fingerprint region across the CH4-air flame: CH4 dissociation, H2 synthesis and consumption, mass diffusion, and fuel/oxidizer mixing.
