Relaxation oscillations between Marangoni cells and double diffusive fingers in a reactive liquid¨Cliquid system

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• 作者：Karin Schwarzenberger ; Kerstin Eckert  ; ;   ; ^{kerstin.eckert@tu-dresden.de} ; Stefan Odenbach
• 关键词：Convective transport ; Mass transfer ; Marangoni instability ; Pattern formation ; Reactive flow ; Surfactants
• 刊名：Chemical Engineering Science
• 出版年：2012
• 出版时间：22 January 2012
• 年：2012
• 卷：68
• 期：1
• 页码：530-540
• 全文大小：2052 K

文摘

We study a novel kind of coupling in chemo-hydrodynamic pattern formation driven by a neutralization reaction along a plane interface separating two immiscible liquid phases. The neutralization reaction, during which a surface-active carboxylic acid is converted into a surface-active salt, gives rise to numerous cycles of relaxation oscillations between a fast cellular Marangoni convection with parallel-acting density plumes and a slow finger convection. By means of particle image velocimetry the dynamics of the sub-structured Marangoni cells are characterized while their geometrical aspects are analysed using shadowgraphy. Based on concentration-dependent density measurements and experiments with miscible solutions, the finger convection could be clearly identified as a double-diffusive phenomenon. Furthermore, the interaction of the sub-structured Marangoni cells with the density effects is examined.