Masters Theses

Keywords and Phrases

aerodynamic levitation; containerless processing; high pressure

Abstract

"This research focused on the development and testing of a hyperbaric aerodynamic levitator for container less materials research of specimens at temperatures greater than 2000°C and pressures up to 10.3 MPa (1500 psi). The effect of specimen size, specimen density, pressure, and flow rate on the levitation behavior was studied. Lightweight specimens demonstrated two stable levitation regimes that were speculated to be associated with a change in the turbulent wake structure. The hyperbaric aerodynamic levitator was also used to determine the effect of pressure on the heat transfer by studying the melting behavior of a levitated 3.0 mm diameter alumina sphere melted with a continuous wave CO2 laser. The convective heat transfer coefficient increased threefold from atmospheric pressure to 10.3 MPa. However, the additional output laser power necessary at 10.3 MPa was only approximately 60 W, demonstrating the feasibility of the system. To demonstrate the benefits of high reactive gas pressure, further melting studies with aluminum oxynitride and chromium nitride were completed. Aluminum oxynitride specimens were melted in N2 at atmospheric pressure and 10.3 MPa to determine the effect of gas pressure on the phase composition. Preliminary X-ray diffraction results indicated a difference in phases present at atmospheric pressure and 10.3 MPa. A net mass loss of 5.68 wt.% was observed at atmospheric pressure, while at 10.3 MPa, the mass loss was 0.27 wt.%. Similarly, chromium nitride samples were melted in N2 at atmospheric pressure and 5.52 MPa (800 psi) to determine the effect of gas pressure on the phase composition. A more significant mass loss of 60.22 wt.% was noted at atmospheric pressure compared to the 23.64 wt.% mass loss at 5.52 MPa"--Abstract, p. iv

Advisor(s)

Lipke, David W.

Committee Member(s)

Newkirk, Joseph William
Watts, Jeremy Lee, 1980-

Department(s)

Materials Science and Engineering

Degree Name

M.S. in Materials Science and Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Spring 2023

Pagination

xiii, 78 pages

Note about bibliography

Includes_bibliographical_references_(pages 71-77)

Rights

© 2023 Sydney Elizabeth Boland, All Rights Reserved

Document Type

Thesis - Open Access

File Type

text

Language

English

Thesis Number

T 12241

Electronic OCLC #

1426046800

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