Experimentally Derived Scaling Laws from Spatiotemporally Resolved Measurements in High-Pressure Combustors

The objectives of this research effort are to experimentally derive the scaling laws up to 30 bar for key combustion species and temperature for reactions involving various hydrocarbon fuels in such a way so that the spatio-temporally resolved measurements would not be influenced by signal-degrading processes such as quenching, photolytic interference, Stark shift, and stimulated Raman. This builds on successful Phase-I measurements of atomic species (e.g., O atom) and CO using two-photon laser-induced fluorescence (TPLIF) at high pressures for the first time. During the Phase-II effort we will focus on methodologies for achieving scaling laws for temperature and major species (e.g., (N2, O2, CO2, CH4, and C2H4) using hybrid fs/ps coherent anti-Stokes Raman scattering (fs/ps CARS). In addition, collision-free measurements of minor species (e.g., OH, CH, HCO, CH2O, and HO2) will be investigated at high pressure using electronic resonant enhanced (ERE) CARS. Finally, strategies for achieving quenching-free TPLIF measurements using short time gating and/or streak-camera detection will be investigated for atomic species (e.g., O and H atoms) and molecular species (e.g., CO). Experiments will be conducted in flat flames and strained flames at pressures up to 30 bar or even higher for developing pressure-scaling laws using finite-rate chemistry models.