METHANE FLOW IN ORGANIC NANOTUBES OF COMPLEX GEOMETRIES

MARIANO MARTÍN ; MARCOS FEDERICO CASTEZ; EMILIO WINOGRAD; VERONICA M. SANCHEZ

Los Polvorines, Buenos Aires

Workshop; Transport Phenomena and Non-Equilibrium Processes; 2018

UNGS

Whilein macroscopic pipeline flows the interaction between fluid moleculesdominates the flow behavior, in the case of flow in nanochannels,often is the interaction of fluid molecules with the tunnel´s wallswhich more deeply impacts on the flow properties. Moreover, thesenanoscale flows are usually associated with the formation of anadsorbed mobile layer. When the tunnel´s walls are smooth enough, theflow rates are strongly enhanced with respect to the one calculatedby the continuum analytical equations (Hagen-Poiseuille, Knudsendiffusion, etc.). To understand this behavior, numerous experimentaland numerical studies have been performed.Onthe numerical side, the Molecular Dynamics technique has emerged asone of the most valuable and promising tools to simulate andunderstand these systems. Many works consider the flow through poresconnected by carbon nanotubes. Regarding the application to manyreal-life nanochannels (for instance, nanoporous shale rock), whosetypical shapes are far more complex than a smooth cylindricalgeometry, it is necessary to consider nanochannels with complexgeometries. Inthis context, in this work we apply molecular dynamics to simulatemethane flow between pores connected by nanosized channels withdifferent geometrical properties such as tortuosity and surfaceroughness. In particular, we consider two types of tortuosity: one´smooth´ (helicoidal type) and another with more abrupt (spline type)variations of the curvature. We found that the flow rate not onlydecreases as the tortuosity increases but, in addition, curvaturevariations also impact strongly in the flow rate. On the other hand,we carry out simulations in corrugated tunnels, studying how the flowrate depends on the amplitude and wave-length of the corrugationcomparing with the expectations from continuum hydrodynamic models. We compare results from discrete molecular dynamics with results fromcontinuum Lattice-Boltzmann method, using equivalent correspondingnanochannels.Finally,we discuss the application of these results to unconventionalhydrocarbon reservoirs (shale type), which are formed byinterconnected nanopores with complex geometries.p { margin-bottom: 0.25cm; direction: ltr; line-height: 120%; text-align: left; }p.western { font-size: 11pt; }p.cjk { font-size: 11pt; }a:link { color: rgb(0, 0, 255); }