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Visualization of meso‐ and micro‐mixing status in flow system by high speed stroboscopic microscopic photography
Author(s) -
Chen Jianfeng,
Chen Bin,
Chen Gantang
Publication year - 1993
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450710619
Subject(s) - mixing (physics) , turbulence , dispersion (optics) , visualization , materials science , flow (mathematics) , photography , elongation , stroboscope , homogeneous , mechanics , flow visualization , eddy , high speed photography , optics , physics , computer science , statistical physics , composite material , artificial intelligence , art , quantum mechanics , visual arts , ultimate tensile strength
Abstract A new visualization technique, the High Speed Stroboscopic Microscopic Photography with spatial resolution of 6.7 m̈m and time resolution of 8 m̈S 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 λ 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 λ K are dispersed into ones of sizes of λ K , (2) stochastic elongation and/or stretching, and (3) molecular diffusion, by which the whole system becomes homogeneous in the molecular scale.