(128j) Experimental Study of Turbulent Reactive Mixing In a Confined Rectangular Jet Reactor

A detailed understanding of the turbulent reactive mixing is crucial to the design and optimization of chemical reactors. While turbulent shear flows have been studied extensively through the years, the coupling between the mixing process and chemical reaction is far from being clearly understood. This limitation is due to the lack of suitable experimental data. To address this shortcoming, the use of reactive planar laser-induced fluorescence (PLIF) can be a powerful technique for obtaining the knowledge of these reactive-diffusive flows.

The reactive PLIF experiments are being carried out in a liquid-phase confined rectangular jet reactor. A simple diffusion-limited acid-base reaction is employed in the reactive PLIF. A turbulent jet flow case with a 1:2:1 velocity ratio of three streams (acid/base/acid) is being investigated at a Reynolds number based on channel hydraulic diameter of 20,000. Disodium fluorescein, a dye whose fluorescence is strongly pH-sensitive, is uniformly premixed with both the acid and base solutions. The fluorescence transition is made very sharp by carefully adjusting the concentrations of the acid and base solutions. Hence, the acid/base region and reaction interface can be visualized and determined precisely down to a very small scale. The normalized experiment data indicate the percentage of the subgrid scales where the base mixture fraction is above the threshold in the area one pixel covers. The fluid flow is illuminated by a 490nm dye laser, pumped by a Nd:YAG laser, and a 12-bit CCD camera with a spatial resolution of 1024 x 1280 px² is used.

The experimental data are employed to validate the performance of computational fluid dynamics (CFD) models for chemical reactions in turbulent liquid flow.