Modeling the transport of nanoparticle-filled binary fluids through the porous medium: a lattice Boltzmann approach
Understanding the transport of multi-component fluids through the porous medium is of great importance for a number of technological applications, ranging from ink jet printing, the production of textiles and enhanced oil recovery. The process of capillary filling is well understood for a single-component fluid, however much less attention has been devoted to the behavior multi-phase fluids, and especially to nanoparticle-filled fluids, in porous media. Here, we examine the behavior of binary fluids containing nanoparticles that are driven by capillary forces to fill well-defined pores of porous material. To carry out these studies, we use a hybrid computational approach that combines the lattice Boltzmann model for binary fluids and a Brownian dynamics model for the nanoparticles. The hybrid model allows us to capture the interactions between the binary fluids and the nanoparticles, as well as model the interactions among the fluid, the nanoparticles and the pore walls. We show that the nanoparticles dynamically alter both the interfacial tension between the two fluids and the contact angle on the pore walls; this, in turn, strongly affects the dynamics of the capillary filling. We demonstrate that by tailoring the properties of the nanoparticles, such as their affinity to the fluid components and their interaction with the pore walls, we can effectively control not only the filling velocities, but also the deposition of nanoparticles on the pore walls. Our findings provide fundamental insights into the dynamics of this complex multi-component system, as well as potential guidelines for a number of technological processes that focus on capillary filling with nanoparticles in porous media and in microchannels with differing geometries.
Updated: Aug, 2011