QUANTITATIVE MOLECULAR-MIXING MEASUREMENTS USING DIGITAL PROCESSING OF ABSORPTION IMAGES

Absorption imaging was used to measure the chemical product formed in a nonpremixed reacting turbulent water-jet. A collimated light-beam wa s absorbed by red phenolphthalein formed through a chemical reaction b etween neutral (pH 7) jet fluid and alkaline tank fluid. The integrate d absorption was imaged on a CCD camera. Standard single-point absorpt ion technique was thus extended to allow simultaneous measurement of a bsorption over a two-dimensional held. Digital image processing techni ques were applied to obtain the time-average of the integrated chemica l product. Product-concentration profiles in the natural jet were obta ined using Abel inversion. The chemical product present six diameters downstream of the jet exit was increased 35 percent by the addition of two tabs.