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Hydrodynamic stability of marangoni films:II. A Preliminary analysis of the effect of interphase mass transfer
Author(s) -
Wang K. H.,
Ludviksson V.,
Lightfoot E. N.
Publication year - 1971
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690170622
Subject(s) - interphase , marangoni effect , laminar flow , surface tension , instability , mass transfer , mechanics , perturbation (astronomy) , chemistry , thermodynamics , physics , genetics , quantum mechanics , biology
The stability of vertical laminar falling films subjected to interphase mass transfer and surface‐tension gradients in the direction of flow is investigated by linear perturbation analysis. The perturbations considered are vertical waves or rivulets as described by Ludviksson and Lightfoot for nonisothermal films. Perturbations of this type are thought to lead to the maldistribution of flow observed in distillation and gas absorption by Zuiderweg and Harmens and by Francis and Berg. Three unstable regions are predicted, one corresponding closely to that found by Ludviksson and Lightfoot, and two new ones, previously unreported, resulting from interphase mass transfer across the free surface. These predictions confirm the conclusions of Zuiderweg and Harmens for situations in which surface tension increases upward, and they provide a means of estimating the range of unstable gradients. Experimental evidence for instability predicted when the surface tension increases downward is inconclusive. Further investigation of this region, which is of considerable importance, is recommended.