par Wang, Ji-Peng ;Gallo, Elena;Francois, Bertrand ;Gabrieli, Fabio;Lambert, Pierre
Référence Powder technology, 305, page (89-98)
Publication Publié, 2016
Article révisé par les pairs
Résumé : Capillarity in wet granular materials induces cohesion and increases the material strength due to the attractiveforces acting on capillary bridges. In the funicular state, water bridges may be not only formed between twograins but also binding three or more particles, which breaks the axial symmetry of the liquid bridge. Thiswork presents a fundamental study on capillary forces and rupture behaviours of funicular water bridges betweenthree spherical bodies at equilibrium (or static) configurations. Funicular water clusters are numericallysolved by an energy minimization approach. Experimental comparisons are made by measuring capillary forcesand these confirm the validity of the numerical solutions. Evolutions of capillary forces and rupture distances areinvestigated systematically by moving two spheres away from the centre. The fixed water volume condition andthe constant mean curvature condition are studied respectively. Comparisons are made between the un-coalescedpendular liquid rings and the coalesced funicular bridge. For a same fixed total water volume, the capillaryforce is weakened by water bridge coalescence to a funicular bridge when the spheres are packed together, butthe situation may vary for different contact angles and inter-particle distances. For the constant mean curvaturecondition, water bridge coalescence does not alter capillary force significantly when particles are packed closely,but the discrepancy is larger by increasing the gap. Funicular water bridge rupture criteria are also proposedbased on the studied configurations. It is observed that in general the transmission from pendular to funicularstate extends the rupture distance when it has a relatively high water volume or low air-water pressuredifference.

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