Scientists at Spectral Energies have been involved in the application of a wide range of combustion diagnostics for propulsion systems. This includes:
- Simultaneous planar laser-induced fluorescence (PLIF) and laser-induced incandescence (LII) in swirl stabilized flames.
- Dual-pump, dual-broadband coherent anti-Stokes Raman scattering (CARS) for studies of alternative fuels.
- Ultraviolet and infrared diode-laser absorption spectroscopy for high-speed temperature and species concentration measurements.
- High-speed imaging of ignition and flame structure in high-pressure swirl stabilized and trapped vortex combustors.
- Studies of canonical flames for model validation, including turbulent jet flames, bluff-body flames, and counterflow flames, among others.
Figure 1. The simultaneous OH PLIF/LII images shown above illustrate the formation of rich, unburned pockets of fuel and air that promote soot formation in swirl stabilized spray flames. The LII marks the soot and the OH PLIF marks the combustion zone. The extent of the unburned pockets and the corresponding soot volume fraction increases with equivalence ratio.