Doctoral Dissertations

Abstract

"This study consisted of an examination of both the effects of nucleate boiling on polymer coated surfaces and the effects of the polymer coated surfaces on the nucleate boiling curve. The nucleate boiling curve (the curve resulting from plotting heat transferred per unit area versus the temperature difference between the boiling surface and the liquid pool) of the polymer coated surfaces were compared with the nucleate boiling curve of gold-plated surfaces with no polymer coat and it was found that the thicker the polymer coat, the more the curve deviated from that of the metal uncoated surfaces.

All surfaces were examined before and after boiling with a scanning electron microscope (SEM) and it was found that boiling caused the polymer coated surfaces to change. In some cases the polymer coated surfaces cracked and small pieces of polymer were lifted from the surface while on other surfaces the polymer was eroded. However in two cases, the polymer coating cracked and part of the polymer was lifted off the surface. The holes formed in the polymer had some polymer still remaining in the bottom of the holes.

Hysteresis, in the form of scattered data, was noticed when the surface had not been aged properly. Since this phenomenon was noticed on more than one surface and the surfaces were found to be clean when examined with the SEM, the hysteresis effects were attributed to inactivated nucleation sites. Hysteresis caused by absorbed inert gases was ruled out due to the controlled atmosphere on the surface before the liquid covered the surface.

Data was also taken at critical heat flux. The temperature difference between the boiling surface and the liquid pool was taken at one-minute intervals and it was found that for the polymer coated surfaces the transition from nucleate boiling to film boiling was much slower than for uncoated surfaces.

Heat transfer from polymerized tetraflouroethelene coated surfaces was much greater than for uncoated surfaces at moderate heat fluxes. This phenomenon along with the slow transition from nucleate to film boiling observed in this study could be of considerable industrial importance"-- Abstract, pp. ii-iii

Advisor(s)

Park, Efton

Committee Member(s)

Gaddy, J. L.
Mayhan, Kenneth G.
Johnson, James W., 1930-2002
Flanigan, V. J.

Department(s)

Chemical and Biochemical Engineering

Degree Name

Ph. D. in Chemical Engineering

Publisher

University of Missouri--Rolla

Publication Date

1973

Pagination

ix, 125 pages

Note about bibliography

Includes bibliographical references (pages 78-82)

Rights

© 1973 David Franklin Warner, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 4092

Print OCLC #

5985299

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