Quantitative Analysis Of Flow Through Permeable Media In Microfluidic Devices

Download or read book Quantitative Analysis of Flow Through Permeable Media in Microfluidic Devices written by Jindi Sun and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multiphase flow through permeable media is sophisticated in nature because phases interact at pore scale and compete for permeability. This complexity and non-linearity make predictive mathematical descriptions a challenging task. Remediation of aquifer NAPL (non-aqueous-phase liquid) contamination is an example of an application where predictive models are highly desirable. This dissertation presents an experimental program that uses a microfluidic experiment at form, a high-resolution camera, and a microscope-mountable high-speed camera to examine i) the flow behavior of remediation of aquifer contamination using CO2 foams that are stabilized with nanoparticles, ii) transient flow states in single-phase flow, and iii) occurrence of Haines Jump in two-phase flow using an evolution graph produced through interface tracking. Contamination caused by NAPL in aquifers and soil presents a big challenge and affective remediation techniques are desired. This work considers CO2 foams for remediation of NAPL contaminated porous media. However, CO2-surfactant foam is not stable enough for efficient removal of NAPL contamination. This shortcoming may be alleviated via the NP-surfactant mixture as a stabilizing agent. The first part of work focuses on the use of fly ash NPs and a mixture of AOS and LAPB surfactants to generate stable foams. This work presents results from an experimental program that was designed to establish optimum concentration of the foam’s constituents. Results indicate that fly ash, which is a by-product of coal-burning power plants, is a suitable material to generate robust CO2 foams. Moreover, the results suggest for 1000 ppm AOS-LAPB surfactant solution, 1000 ppm fly ash NPs is the best choice. What’s more, foam generated in channels is discontinuous and the solid sediment in NAPL can weaken the mobility and performance of foam. The flow system is too complex to study the mechanics behind the multi-phase flow. Hence, simplified microfluidic devices and advanced techniques are applied in the second and third part of the dissertation. The classic multiphase extension for Darcy's law models this complexity through two practices: per-phase application of Darcy's law with relative permeability and instantaneous resolution of fluid dynamics at pore scale. Experimental evidence against the latter practice is provided in the second part in the dissertation for single-phase experiments. The third part of the dissertation targets the former assumption by examining Haines Jump, a type of rapid pore-filling event in multiphase flow through permeable media better known as Haines Jump. Segmentation and tracking techniques are applied to extract and track displacement fronts as they evolve through high-speed video recording. The resulting evolution graph facilitate topology-cognitive computation on the transport network. These experiments conclusively identify Haines Jump in microfluidic devices and qualitatively analyze their significance to Darcy's law in the macroscopic scheme of bulk flow rates.