Dresden 2009 – wissenschaftliches Programm
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SYSO: Symposium Self-organizing Surfaces and Interfaces
SYSO 7: Self-Organizing Surfaces and Interfaces VI
SYSO 7.3: Vortrag
Donnerstag, 26. März 2009, 16:15–16:30, GÖR 226
The dynamics of reaction fronts under different level of gravitational acceleration — •Kerstin Eckert1, Armin Heinze1, Laurence Rongy2, Anne De Wit2, and Stefan Odenbach1 — 1Institute for Fluid Dynamics, Chair of Magnetofluiddynamics, Technische Universität Dresden, D-01062 Dresden — 2Nonlinear Physical Chemistry Unit, CP 231, Faculté des Sciences, Université Libre de Bruxelles, 1050 Bruxelles, Belgium
When two separate solutions of chemicals A and B, reacting according to the simple kinetic scheme A+B gives C, are brought into contact, the reaction takes place in a localized region, the reaction front. The propagation of such fronts was studied intensively in the past (e.g. Gálfi and Rácz, Phys. Rev. E 38, 3151, 1988) due to their relevance for biological or other physical systems, too. It was indicated recently (Shi & Eckert, Chem. Eng. Sci. 61, 5523, 2006 and Rongy et al. Phys. Rev. Lett. 101, 084503, 2008) that the propagation of these fronts is affected by gravity which leads to a faster motion as predicted by Gálfi and Rácz. We present an experimental study of an immiscible solvent combination placed in horizontal Hele-Shaw cell. A, B and C refer here to acid, base and salt, respectively. We analyse the dynamics of the resulting neutralization front by means of shadowgraph visualization and differential interferometry. The detailed comparison of ground-based and microgravity experiments strongly supports the idea that the reaction front propagation is caused by the interaction between reaction and diffusion with a pair of buoyancy-driven roll cells.