WIT Press

Evaluation Of Mixing Energy In The Swirling And Baffled Flasks


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V. J. Kaku, M. C. Boufadel & A. D. Venosa


A USEPA laboratory screening protocol for dispersants effectiveness consists of placing water, oil, and dispersants in a flask placed on an orbital shaker. Two flasks are being investigated, the Swirling Flask and the Baffled Flask. The BF contains baffles that induce an over-and-under type of mixing that somewhat better simulates breaking waves. We use hot-wire anemometer to measure the velocity distributions in both flasks rotating at a speed of 150 rpm. The measurements were conducted in small portions near the centers of the flasks. We found that the average velocity in the BF was about 5 times larger than that in the SF. The velocity in the BF was essentially uniform with depth, while that in the SW decreased sharply with depth. The computed energy dissipation rates per unit integral length scale were about 0.03 and 0.92 in the SF and the BF, respectively. 1 Introduction There have been many studies dealing with oil dispersion since the late 70’s. The evaluation of the effectiveness of a particular dispersant at sea has been hampered by large experimental uncertainties in the sea. For this reason, various governmental agencies have adopted laboratory experiments. The effectiveness