MR003-0018
Theoretical Study of Mixing and Fluid Miscibility in Microchannels
Theoretical Study of Mixing and Fluid Miscibility in Microchannels
Monday, 14 December 2020
Poster
Abstract:
The increasing demand for carbon sequestration as a means to address escalating atmospheric carbon dioxide levels prompts new studies to understand miscible and immiscible fluid interactions in the subsurface. As anthropogenic CO2 emissions are stored underground or repurposed for hydraulic fracturing and enhanced oil recovery applications, supercritical CO2 and other subsurface fluids interact, convect, and diffuse through microscopic, connected pores, rock fissures, and fractures. A better understanding of fluid mixing and miscibility behaviors on the microscale thereby assists in predicting and controlling underground fluid injection as well as improves the rate of success and efficiency of such processes.
This project investigates fluid interactions and scrutinizes the development of microscopic mixing as fluid flows through microchannels. Computational fluid dynamics are used to study such phenomena and explore possible relationships between the rate of injection and the development of miscibility. The results of this study are used to construct a quantitative model to explain the miscibility behavior between different fluids.
For the purpose of this study, a micro-capillary loop (500 µm wide by 30 µm deep by 2.47 m long) without obstacle units is reproduced and used as input to a fluid dynamics simulator, OpenFOAM. Simulations are designed incorporating two identical liquids of different colors, injected through Y-shaped inlets allowing them to flow in parallel through the entire length of the channel as they visibly mix due to diffusion. The velocities are chosen so that a small Reynolds number (< 1), comparable to those of porous media, is maintained. Each velocity is simulated several times with progressively tighter levels of mesh refinement and tolerance to ensure accuracy. The phase value alpha (0-1, where 0.5 indicates a completely mixed area) is recorded at incremental distances from the inlet. Exponential curves are fitted through the simulation results and are used to explain the relationship between the rate of injection and length of mixing.
This project investigates fluid interactions and scrutinizes the development of microscopic mixing as fluid flows through microchannels. Computational fluid dynamics are used to study such phenomena and explore possible relationships between the rate of injection and the development of miscibility. The results of this study are used to construct a quantitative model to explain the miscibility behavior between different fluids.
For the purpose of this study, a micro-capillary loop (500 µm wide by 30 µm deep by 2.47 m long) without obstacle units is reproduced and used as input to a fluid dynamics simulator, OpenFOAM. Simulations are designed incorporating two identical liquids of different colors, injected through Y-shaped inlets allowing them to flow in parallel through the entire length of the channel as they visibly mix due to diffusion. The velocities are chosen so that a small Reynolds number (< 1), comparable to those of porous media, is maintained. Each velocity is simulated several times with progressively tighter levels of mesh refinement and tolerance to ensure accuracy. The phase value alpha (0-1, where 0.5 indicates a completely mixed area) is recorded at incremental distances from the inlet. Exponential curves are fitted through the simulation results and are used to explain the relationship between the rate of injection and length of mixing.