Degree Type

Dissertation

Date of Award

2019

Degree Name

Doctor of Philosophy

Department

Mechanical Engineering

Major

Mechanical Engineering

First Advisor

Baskar Ganapathysubramanian

Abstract

Precise and passive manipulation of particles in microscale flow channels is of interest to promising challenges in chemical, biomedical and bioengineering applications such as particle separation, ordering, cell-detection and analysis. Ease of operation, low sample-volumes, portability, cost-effectiveness, and scalability, are some of the compelling benefits in these technologies as opposed to active-manipulation systems requiring additional machinery for flow and/or particle control, which are invariably disadvantageous in one or more of the above aspects. The motion of particles and their equilibrium (if any) in such flows directly depends on their shape and parameters such as channel geometry and fluid/particle inertia. As such, a significant portion of these applications can be described by steady-state physics models, and the current work details methodologies that leverage this advantage to address two primary aspects under inertial flows: development and experimental validation of a quasi-dynamic computational framework to characterize \textit{focusing} positions for spherical particles (the forward problem) and extending this framework to design particle geometries for certain desirable long-term characteristics in flow such as non-tumbling/bobbing modes for self-alignment in flow (the inverse problem). The former is relevant in scenarios outlined above where particle geometries are known and it is desired to understand trends in focusing patterns of particles for configurations defined by parametric sweeps over arbitrary channel geometries (based on cross-section, curvature, etc.), flow speeds, and channel confinements, where the configuration space quickly becomes prohibitively expensive for experiments. The latter however has only gained momentum over the past few decades, with work being mostly analytical/empirical in nature and restrictive due to simplifications such as zero-inertia, unbounded domains, linear shear etc. The frameworks developed herein are extensible to incorporate additional flow physics such as non-Newtonian fluids, and envisioned to provide thumbrules for the microfluidics community for further work in this burgeoning field concerning next-generation microfluidic cell analysis devices.

Copyright Owner

Aditya Kommajosula

Language

en

File Format

application/pdf

File Size

189 pages

Share

COinS