(97c) Advanced Laser Diagnostics Measurements for Reactive Mixing Flows

The development and application of advanced laser diagnostic techniques for reactive mixing flows are described.  Techniques to be discussed include high-data-rate planar imaging techniques such as OH planar laser-induced fluorescence (PLIF).  We discuss the acquisition of OH PLIF images at data rates of 5 kHz.  Planar imaging techniques for measuring the extent of molecular mixing in nonreacting flows are also discussed.  Coherent anti-Stokes Raman scattering measurements of reactive mixing processes are also discussed.  Dual-pump CARS is used for the simultaneous measurement of temperature and species concentrations.  Recent measurements of concentration and temperature fields using dual-pump H₂/N₂ CARS for a reactive jet in crossflow in a high-pressure combustion test rig are discussed.  We also discuss the use of ultrafast laser systems for measurements in reactive mixing flows.  We have demonstrated the use of ultrafast laser systems for 5 kHz temperature measurements in flames using chirped-probe-pulse femtosecond CARS.  We also present the results of recent femtosecond CARS measurements in turbulent nonpremixed jet flames, and discuss the potential for concentration measurements using this technique.