2011/03/28 by F. Leoni, Fabio Leoni, Édouard Kierlik +8
Chemistry · Engineering · Physics and Astronomy · #Aerogels and thermal insulation #Disordered Systems and Neural Networks (cond-mat.dis-nn) #FOS: Physical sciences #Quantum, superfluid, helium dynamics #Spacecraft and Cryogenic Technologies #cond-mat.dis-nn
paper · pdf · doi:10.48550/arxiv.1103.5370
13 pages, 16 figures
arxiv created 2011/03/28 · openalex publication_date 2011/03/28 · arxiv updated 2011/03/29 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We present a theoretical study of spontaneous imbibition of liquid 4He in silica aerogels focusing on the effect of porosity on the fluid dynamical behavior. We adopt a coarse-grained three-dimensional lattice-gas description like in previous studies of gas adsorption and capillary condensation, and use a dynamical mean-field theory, assuming that capillary disorder predominates over permeability disorder as in recent phase-field models of spontaneous imbibition. Our results reveal a remarkable connection between imbibition and adsorption as also suggested by recent experiments. The imbibition front is always preceded by a precursor film and the classical Lucas-Washburn scaling law is generally recovered, although some deviations may exist at large porosity. Moreover, the interface roughening is modified by wetting and confinement effects. Our results suggest that the interpretation of the recent experiments should be revised.