- Title
- Numerical investigation of micromixing enhancement
- Creator
- Khezerloo, Marzieh
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2023
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Microfluidics found wide-ranging applications across various fields. One common requirement in many of these applications is the need to mix two or more fluids effectively. This has led to the emergence of micromixers, which play a crucial role in achieving efficient mixing within microfluidic systems. In microfluidics, the flow regime is predominantly laminar, characterized by a low Reynolds number. Consequently, mixing predominantly occurs through molecular diffusion, which, since it is a slow process, often necessitates long channels. This poses challenges in micromixers whose dimensions are very small, thus prompting researchers to explore methods for accelerating the mixing process. Recent advancements in the field of micromixing resulted in the development of numerous techniques aimed at improving mixing; these techniques are broadly categorized as passive and active techniques. Passive techniques rely on the interaction between the flow and the micromixer’s design to promote mixing. By manipulating the micromixer’s geometry, it is possible to generate transverse vortices, which can enhance mixing quality. On the other hand, active techniques require external energy to disrupt the laminar flow pattern, facilitating faster and more efficient mixing. This study aims to investigate the combination of passive and active techniques to enhance micromixing. Specifically, the study explores the incorporation of roughness elements on the micromixers’ walls as a passive technique, along with the introduction of blowing or injecting subsidiary flows as an active technique. Furthermore, the integration of this combined approach with split and recombine methods, as well as curved micromixers, is also examined. The obtained results demonstrated that the proposed combination significantly enhances the mixing performance in straight micromixers. Furthermore, when integrated with curved micromixers, the combination reinforced centrifugal effects and intensified secondary flows, leading to further improvement in mixing performance. Moreover, employing the proposed technique as a pre-mixing unit for split and recombine micromixers yielded a substantial increase in their mixing indexes.
- Subject
- micromixer; CFD; mixing; blowing; suction; rough wall
- Identifier
- http://hdl.handle.net/1959.13/1499310
- Identifier
- uon:54645
- Rights
- This thesis is currently under embargo and will be available from 27.10.2024, Copyright 2023 Marzieh Khezerloo
- Language
- eng
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