Capillary Flow through Partially Saturated Fibrous Wicks

Heat pipes are devices capable of transferring heat at a high rate between a thermal source and sink having only a small temperature difference between them. The crucial element of a heat pipe is the wick, through which condensed liquid from the cooler region returns to the hotter region under the action of capillary pressure. The purpose of the present work is to study, both theoretically and experimentally, flow through highly porous fibrous material, which is often used for heat-pipe wicks. Of particular concern is operation of wicks near their capillary limit where they are only partially saturated.