Absorption of microdroplets by layered porous media

Abstract

Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.The subject of this paper is the sequential absorption of two droplets at its arbitrary location on the surface of single- and double-layer porous media. The consideration is based on simultaneous solution of the equations describing liquid flow in the droplet and equations of unsteady filtration in the porous medium. The layers of porous medium were characterized by effective permeability coefficients dependent on porosity and pore size. The change in the droplet shape during absorption and the propagation of absorbed fluid in a porous medium are the output data of the problem. The effect of porous medium structure parameters and relative location of droplets on the rate of absorption and distribution of absorbed liquids is analyzed using the numerical experiment. It is shown that the presence of the second layer can significantly affect the duration and result of droplet absorption. The ratio of the pore size in the layers is found to be the main parameter that governs the effect of the second layer.