Imbibition in microchannels*

In this work we studied the imbibition in straight microchannels with circular and noncircular cross-sections. The formulation of a motion equation allowed us to obtain closed-form analytical solutions for the imbibition front when there is an initial head pressure P, the gravity is acting, and the cylinder may be inclined any angle respect to the vertical. It is shown that the limit case, Bo=0, where Bo is the Bond number, give solutions that cover the main aspects related to imbibition in microchannels, as the competition between the strength of the capillary phenomena and the hydraulic resistance depending on the shape.