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DY: Fachverband Dynamik und Statistische Physik

DY 29: Posters II

DY 29.30: Poster

Donnerstag, 29. März 2012, 17:00–19:00, Poster A

Spontaneous imbibition in a network of nanopores: A numerical study — •Zeinab Sadjadi and Heiko Rieger — Saarland University, Saarbrücken, Germany

We study numerically the spontaneous imbibition of water into nanoporous Vycor glass (NVG). NVG is a silica substrate with an interconnected network of cylindrical pores with characteristic radii of 3-5 nm, which we model by a two-dimensional network of cylindrical pipes with random radii and different aspect ratios. We model the spontaneous rise of water by solving the mass balance equation at each node. We analyze the temporal evolution of the average height and width of the invasion front. Our results predict an unusually weekly correlated menisci motion and an anomalously strong roughening of imbibition fronts. These findings, which are also observed experimentally by neutron imaging, show that spontaneous imbibition crucially depends on pore aspect ratio and reveal a new universality class of imbibition behaviour which is expected to occur in any matrix with elongated pores.