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AbstractWe have developed a throat-bulb network model to simulate multiphase flow experiments. The model has been efficiently implemented on massively parallel computers (MasPar and eM5). This model has allowed us to study the dynamics of displacement processes. Using grids of size 64 x 64 x 128 (half a million cells), we are able to incorporate random variations in the throat and pore size distributions and observe flow patterns such as viscous fingering, stable front displacement, and invasion percolation. Furthermore, we are able to discern certain scaling rules in terms of macroscale variables.Displacement processes in a network model with random distribution of throat and pore size can be characterized by three parameters: M (viscosity ratio), Ca (capillary number), and Cg (the ratio of capillary number and Bond number). Macroscale variables, f{ rand Sor, are strongly dependent on flow patterns, whereas the dynamic capillary pressure, Pc, is independent of flow patterns.Analysis oflaboratory measurements of these macroscopic variables is generally based on steady state approximations and moreover, it offers no clue as to how one might extrapolate the results to the reservoir scale. Using the pore network simulator, we can model dynamic flow behavior and understand the scaling rules for experimental measurements. The simulator will eventually become a practical tool to investigate multi-phase flow in various flow conditions. Furthermore, a better understanding of experimental measurements will help us construct effective grid-block properties for reservoir simulation.
An analytical solution for the transport equation is presented for the case of coupled energy and multicomponent mass transfer in an ensemble of spherical drops, bubbles or solid particles. The solution is used to evaluate the total interfacial transfer rates in a population with particle size and residence time distributions. Using matrix notation and appropriate transformations, the partial differential equations are solved for each phase by using an integral operator whose kernel is the residence time distribution for the flow system. The method of attack is illustrated by solving the transport equations for fine dispersions or suspensions with high hold-up values and presence of adventitious surface active agents.Studies on mass transfer to or from drops, bubbles, or solid particles in continuous media have primarily been limited to studies of isothermal, uncoupled transfer mechanism for a single particle in a binary system. To achieve a useful analysis the assumption is commonly made that the particles have uniform size and residence time distrihutions. This permits calculation of the total interfacial area, and the total transfer rate based on the average size and the average residence time. However, it is well known that in actual practice the particle size as well as the residence time distributions are not uniform and the assumption of uniformity may lead to error.In many practical cases one must also consider the simultaneous transfer of heat and mass in a multicomponent, multiphase system where coupling effects among the various fluxes involved may take place. Hence it is the aim of this study to generalize previous works in uncoupled transport in binary systems ( 1 , 7 to 9, 1 5 ) to cases that involve coupled heat and multicomponent mass transfer in continuous flow dispersed systems with nonuniform particle size and residence time distributions.
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