Quantitative dual-tracer planar laser-induced fluorescence measurements of molecular mixing

Simultaneous, planar laser-induced fluorescence (LIF) images of nitric oxide (NO) and acetone have been used to calculate instantaneous quantitative maps of molecularly mixed jet-fluid fraction in an axisymmetric shear layer. In this experiment, NO is seeded into high-purity nitrogen jet fluid and acetone is seeded into air coflow. On mixing at the molecular level, the NO LIF is strongly quenched by oxygen from the coflow, while the acetone signal is unaffected by the mixing process. The extent to which the jet fluid is mixed at the molecular level is determined on a pixel-by-pixel basis from the simultaneous NO and acetone planar LIF images. Jets at Reynolds numbers ranging from 1000 to 50 000 are investigated.