ABSTRACT
Spontaneous imbibition is a ubiquitous natural and fundamental phenomenon existing extensively in a variety of processes. Based on the fractal characteristics of pore space and tortuous streamtubes/capillaries in natural porous media, this chapter presents a study on characterizing the physical processes in wicking phenomena in air-saturated single tortuous capillary and porous media. For this purpose, the rst section is devoted to brieˆy introducing the fractal theory, and then the fractal characteristics of porous media are given in Section 10.2. In Section 10.3, models for capillary rise in a single capillary and for spontaneous imbibition in porous media are derived, including the effect of gravity and the controversy over the validity of the Lucas-Washburn (LW) equation is also discussed in this section. The results and discussions are presented in Section 10.4, and the summary and conclusions are given in Section 10.5.
