| In this paper the injection dispersion in an oscillatory flow mixer has been studied by using the flow visualization technique with a solution of blue dye as the tracer. The process of injection dispersion was monitored with a digital camera connecting to a computer that treated the video data stream synchronously to obtain the attenuation curve of relative deviation of the flow image's gray scale values. The deviation value was used to characterize the inhomogeneous degree of concentration fields, and the attenuation rate with time was used to characterize the injection dispersion performance of flow field.The experiment was carried out in two situations, without net flow and with net flow. The influence of oscillatory flow Reynolds number (Re0) and Strouhal number (Si) to the injection dispersion performance of OFM was explored. So was the effect of net flow Reynolds numberBy the observation of experimental phenomena and the analysis of experimental data, it showed that the oscillatory parameters Re0 and St had strong correlation with the injection dispersion performance. Proved with the mixing rate using parameters tw and R\^ it showed that large amplitude and high frequency could greatly enhance the mixing rate. But at large St, the rate of attenuation appears to be in periodic fluctuation at the range of low frequency, so there must be some best partnership of amplitude and frequency. When a net flow was introduced, the result seemed to take great changes, but the tendency is the same as that without net flow. The correlation between injection dispersion character and Ren reduces with the oscillatory intensity increasing.The experimental study suggests that OFM reactor should provide high efficient injection dispersion performance with good controllability on the mixing intensity. So it should also satisfy the special requirement of the concentration distribution in the injection area for processes such as flocculation. |
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