A numerical study on microbubble mixer

Guo, Lin

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https://hdl.handle.net/2142/49359 Copy

Description

Title

A numerical study on microbubble mixer

Author(s)

Guo, Lin

Issue Date

2014-05-30T16:40:00Z

Director of Research (if dissertation) or Advisor (if thesis)

Hilgenfeldt, Sascha

Department of Study

Mechanical Sci & Engineering

Discipline

Mechanical Engineering

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Mixing
• Bubble streaming flow
• Dynamical system
• Passive scalar simulation
• Micromixer

Abstract

This text comprises a numerical study of the mixing performance on the micromixer, a device which actuates steady streaming by semi-cylindrical sessile bubble oscillations. The mixer's capability of producing chaotic mixing is confirmed and a numerical simulation that is in good agreement with the experiment is developed, which then leads to the exploration of three mixing schemes. At the beginning, we introduce the experimental configuration of our micromixer, as well as the general framework of computing the asymptotic solution which is later used in numerical simulations. With these fundamentals, we proceed to characterize the efficiency of our mixer, essentially a Hamiltonian dynamical system, using Poincare sections and the Finite-time Lyapunov exponent. These indicators provide evidence that by properly blinking between different streaming patterns, chaotic-like mixing can be created inside our mixer. The observation made from numerical results that the size of the region that is good for mixing is related to the blinking period is substantiated by a scaling argument. After showing that the micromixer is beneficial for mixing from the perspective of dynamical system theory, we then focus on real applications by developing passive scalar simulations that agree with experimental data well. Finally, the establishment of the simulation allows us to explore the efficiencies of three different schemes and to optimize their designs for better mixing.

Graduation Semester

2014-05

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http://hdl.handle.net/2142/49359

Copyright and License Information

Copyright 2014 Lin Guo

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