Abstract

Fluid flow and local heat transfer in a microchannel with single and array of pin fins have been studied. For the single pin fin case, a microchannel with a 150-µm diameter pin fin with a tip clearance was experimentally and numerically studied for three Reynolds numbers in laminar regime. Tip clearances of 0, 30, 45 and 100 µm in a 200-µm high microchannel. Experimental and numerical local temperatures and the corresponding Nusselt numbers along the centerline of the pin fin were presented and discussed. Local temperatures were measured on top of the heater surface and downstream the pin fin through micro resistance temperature detectors (RTDs). A conjugate CFD modeling capable of simulating solid/fluid conduction and convection revealed velocity, heat flux and heat transfer coefficient over the heated surface. Nusselt number and wake length for a range of tip clearances were presented and compared with full-height pin fin. Experimental and numerical results showed that a tip clearance can significantly enhance heat transfer in the wake region. Simulations revealed that tip clearance alters the flow structure by increasing the three dimensionality of the flow, promoting mixing, shortening the wake region, and increasing the velocity downstream the pin fin. A tip clearance with a height of 100 µm was found to provide the best heat transfer enhancement. For a microchannel with array of pin fins with tip clearance, an experimental study carried out with the tip clearance of 0 and 100 µm in a 200-µm high microchannel. Results revealed that introducing tip clearance in pin array can on-average almost double heat transfer coefficient compared to full height (no tip) array of pin fins.

Notes

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Graduation Date

2020

Semester

Summer

Advisor

Peles, Yoav

Degree

Doctor of Philosophy (Ph.D.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Degree Program

Mechanical Engineering

Format

application/pdf

Identifier

CFE0008592; DP0024268

URL

https://purls.library.ucf.edu/go/DP0024268

Language

English

Release Date

February 2024

Length of Campus-only Access

3 years

Access Status

Doctoral Dissertation (Open Access)

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