Document Type

Thesis - Open Access

Award Date

2019

Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering

First Advisor

Todd Letcher

Abstract

Additive manufacturing technology and applications have quickly expanded in many industries over the last five years. As additive manufacturing is studied and refined, improvements in resolution and strength have helped propel further growth of the industry. This study focuses on an additive manufacturing technology called fused filament fabrication (FFF). FFF involves the extrusion and layer-by-layer deposition of a molten thermoplastic material to create the desired part. One potential new application of fused filament fabrication is the manufacture of heat exchangers and heat sinks. This study focuses on developing baseline experimental data related to convective heat transfer coefficients over surfaces of commonly used polymers in FFF 3d printing while varying printing parameters and surface treatments of the samples. A copper pipe containing two cartridge heaters was placed inside the ABS test samples with two thermocouples placed at the surface of the 3d printed material to measure the surface temperature of the cylinder. The samples were tested inside a wind tunnel to measure the effects of surface roughness and printing parameters on heat transfer over a range of velocities. Samples with different printing parameters were tested first. Parts with layer heights (LH) of 0.1 mm, 0.2 mm and 0.3 mm were printed. As the layer height increases the roughness also increased. Sample 1 of LH = 0.1 mm had a roughness of 9.72 μm and a heat transfer coefficient of 72 W/m2-K and sample 1 of LH = 0.3 mm had a roughness of 28.83 μm and a heat transfer coefficient of 85 W/m2-K, with fans operating at 12V. Surface treatment, such as acetone smoothing, sanding and sanding/acetone-smoothing were performed in other to reduce surface roughness. The acetone smoothing process affected more the samples with smaller layer heights. Sample 1 of LH = 0.2 mm had a roughness reduced to 11.43 μm and a heat transfer coefficient of 71 W/m2-K. Sanding and sanding/acetone-smoothing process recorded the smallest values for roughness, while recording the highest values for heat transfer coefficient. Sanded sample 2 of LH = 0.3 had a heat transfer coefficient of 101 W/m2-K and roughness of 4.35 μm.

Library of Congress Subject Headings

Heat -- Convection.
Three-dimensional printing.
Heat -- Transmission.
Heat exchangers.
Materials -- Additives.
Manufacturing processes.

Format

application/pdf

Number of Pages

70

Publisher

South Dakota State University

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Rights Statement

In Copyright