Yang, Kailai
(2020)
Thermal Performance and Pressure Drop of the Compact Heat Exchangers based on DMLS.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
In recent years, direct metal laser sintering (DMLS) has been gradually applied to various fields as an advanced additive manufacturing method. In this study, four printed-circuit-heat-exchanger like (PCHE-like) compact heat exchangers with different channel structures were designed and manufactured by the DMLS method. Performance tests were carried out to compare the thermal performance and pressure drop of these four compact heat exchangers. The compact heat exchangers were tests for air flow rate in the range of 6.5 to 37.7 L/min keeping the hot-side and cold-side inlet temperature fixed at 52 ℃ and 25 ℃, respectively. It was found that the heat exchanger with the most densely arranged circular straight channels had better heat transfer performance and lower pressure drop. Later, scanning electronic microscope (SEM) images and image segmentation techniques were employed to evaluate the surface roughness and geometric features of the heat exchanger channels manufactured by the DMLS method. It showed that the build direction had a great impact on the final quality of the manufactured channel. Channels built in the vertical direction had less surface roughness and geometric feature changes compared to the channels built in the horizontal direction. In addition, comparative study demonstrated that the surface roughness and geometric feature changes of the circular channels were larger than those of the semicircular channels when they were built in the same direction and had the same design hydraulic diameter of 1mm. Finally, circular and semicircular channels with different DMLS built direction were tested to determine their flow resistance by using the Fanning friction factor. Vertically built circular channels showed minimal resistance, while horizontally built circular channels showed maximum resistance.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
29 July 2020 |
| Date Type: |
Publication |
| Defense Date: |
3 April 2020 |
| Approval Date: |
29 July 2020 |
| Submission Date: |
6 April 2020 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Number of Pages: |
74 |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Mechanical Engineering |
| Degree: |
MS - Master of Science |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
DMLS; PCHE; Compact heat exchangers;Thermal performance; pressure drop; SEM; Surface roughness |
| Date Deposited: |
29 Jul 2020 19:20 |
| Last Modified: |
29 Jul 2020 19:20 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/38590 |
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