Laser-induced fluorescence technique for the quantification of mixing in impinging jets

A laser-induced fluorescence (LIF) technique is implemented to measure conc entration profiles and mixing performance in two impinging jet geometries. Experimental results are reported for steady and unsteady (transitional) mi xing of initially segregated miscible fluids. Flow structures visualized by imaging concentration distributions at five vertical planes throughout the mixers. Mixing is quantified for each Reynolds number examined by calculat ing the overall intensity of segregation. Mixing performance varies substan tially as a function of Reynolds number. Optimum operating conditions are i dentified for both impinging jet geometries. The results demonstrate the ab ility of laser-induced fluorescence to quantitatively capture small- and la rge-scale flow structures and accurately and reproducibly quantify mixing p erformance in real time for industrially-relevant mixing devices. The LIF t echnique proves to be an accurate and versatile method to quantify mixing p erformance of miscible fluids.