Author(s): Vu Dinh Hung; Kuniaki Sato; Satoshi Imamura
Linked Author(s): Kuniaki Sato
Keywords: No Keywords
Abstract: The hydraulic resistance acting on dense nonaqueous phase liquid droplets falling through saturated porous media was studied experimentally. The resistance is originated in the friction (or shearing) force and capillary force (or creeping force) in addition to drag force and form resistance of droplet in pore channels. Quantitative scaling has been attained by the coefficient of drag force C_D resulted from surrounding fluid and a comprehensive coefficient of friction force C_f which is additionally imposed on a droplet in the pore space. The goal of this work is to illuminate the mechanism of a single droplet motion through saturated porous media and characteristics of both coefficients CD and Cf. Two kinds of experiments: (1) single immiscible droplet falling through still water in tube; (2) single immiscible droplet descending through saturated porous media made of uniform glass beads, were carried out in a constant temperature laboratory. Using two equations of droplet motions in pore space, it necessarily follows that C_f can be represented by the ratio of the droplet diameter (d) to the mean effective pore size (D～*) r=d/D～*, and a critical droplet diameter r_c is around 0.7.