Advanced Imaging

The central objective of the Advanced Imaging Program is the development and application of laser-based imaging diagnostics for studying reacting flows. Imaging diagnostics provide temporally and spatially resolved measurements over a wide range of length scales. Multi-dimensional measurements are necessary to determine spatial correlations, gradients, flame orientation, curvature, and connectivity. During the past few years, we have focused on planar laser-induced fluorescence (PLIF) techniques for measuring concentrations of radical species central to hydrocarbon conversion as well as conversion rates. Diagnostics are applied to isolated repeatable flow-flame interactions to investigate the effects of flow transients on detailed flame structure. By performing measurements in phase with a highly reproducible forced flow, we can eliminate constraints of temporal resolution and obtain phase-averaged measurements of extremely weak signals. Results from this research should provide new insight into the perturbation of chemical reaction pathways by flow-flame interactions. A complimentary line of research involves the extension of imaging techniques to instantaneous measurements in turbulent flames to study turbulence-chemistry interactions. Recent experiments have contributed to the knowledgebase of turbulent partially premixed jet flames, which are the subject of multiple modeling efforts. Experiments in the Advanced Imaging Program are often coupled with computations performed at Sandia and major universities.

Current research topics include:

• Reaction-rate imaging in turbulent premixed and partially-premixed flames
• Development of imaging diagnostics for C2 species
• Two-photon CO planar laser-induced fluorescence (PLIF) imaging
• Effects of flow transients on flames (e.g. isolated vortex-flame interactions)

Advanced Imaging Laboratory
Contact: Jonathan Frank