Abstract

Recent advancements in microelectronics have increased the need for thermal management systems capable of high heat flux dissipation within significant spatial constraints. One method of increasing local heat fluxes is the fabrication of superhydrophilic materials via micro/nanostructuring of the surface. Superhydrophilic surfaces act in a self-pumping capacity, spreading fluid beyond its intrinsic meniscus length to form thin-films, a process known as "hemiwicking", with practical applications in evaporative cooling, as well as flow, pool, and thin-film boiling. Of particular interest is anisotropic hemiwicking via asymmetric microstructuring. The microscopic asymmetricity of the design induces a macroscopically preferred direction of wicking, which has the potential to be tailored to specific heating configurations for increased efficiencies. In this study, half-conical asymmetric microstructures have been produced via two-photon polymerization, and anisotropic quality has been characterized through the use of high-speed videography. High-speed thin-film interferometry and microscopic side-angle videography are utilized to study the evolution of meniscus curvature during inter-pillar fluid front propagation, which determines driving force via Laplace pressures. Experimental results show increased meniscus curvature in the preferred direction of wicking, and measurements at later time scales are in agreement with traditional curvature scaling laws. Meniscus stability differences are also observed during initial front propagation. These results can be used to help optimize anisotropic hemiwicking designs for use in next-generation heat sinks.

Notes

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Graduation Date

2020

Semester

Spring

Advisor

Putnam, Shawn

Degree

Master of Science in Mechanical Engineering (M.S.M.E.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Degree Program

Mechanical Engineering; Thermo-Fluids Track

Format

application/pdf

Identifier

CFE0007917; DP0023051

URL

https://purls.library.ucf.edu/go/DP0023051

Language

English

Release Date

May 2020

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

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