Capillary Wetting Analysis of the CFE-Vane Gap Geometry
Chen Y, et al. (2008). "Capillary Wetting Analysis of the CFE-Vane Gap Geometry." 46th Aerospace Sciences Meeting and Exhibit
The Vane Gap Capillary Flow Experiments are part of a suite of low-g experiments ﬂown onboard the International Space Station to observe critical wetting phenomena in ‘large length scale’ capillary systems. The Vane Gap geometry consists of a right cylinder with elliptic cross-section and a single central vane that does not contact the container walls. The vane is slightly asymmetric so that two gaps between the vane and container wall are not of the same size. In this study, we identify the critical wetting conditions of this geometry using the Concus-Finn method for both perfectly and partially wetting ﬂuids as a function of container asymmetry. In a cylindrical container in zero-g, single-valued ﬁnite height equilibrium capillary surfaces fail to exist if a critical wetting condition is satisﬁed. This nonexistence results in signiﬁcant redistribution of the ﬂuids in the container. It will be shown that there could be three critical geometric wetting conditions that include one in each gap region and one for a global shift of bulk ﬂuid which, among the three, is the most signiﬁcant.