화학공학소재연구정보센터
Canadian Journal of Chemical Engineering, Vol.71, No.6, 967-970, 1993
Visualization of Meso-Mixing and Micro-Mixing Status in Flow System by High-Speed Stroboscopic Microscopic Photography
A new visualization technique, the High Speed Stroboscopic Microscopic Photography with spatial resolution of 6.7 mum and time resolution of 8 mus was developed and first used in this work to visualize the performance of fluid elements in the meso- and micro-mixing processes. From the large amount of pictures taken by this technique, it was found that the fine structure of micro-fluid-elements having sizes less than lambda(K) looks mainly like slices, especially at higher turbulence in which stochastic elongation and stretching play a dominant role in the deformation of the micro-elements. Finally, the meso- and micro-mixing processes were ascribed as composed of three consecutive stages : (1) turbulent dispersion, by which the large eddies of sizes larger than lambda(K) are dispersed into ones of sizes of lambda(K), (2) stochastic elongation and/or stretching, and (3) molecular diffusion, by which the whole system becomes homogeneous in the molecular scale.