Date of Award

1997

Publication Type

Master Thesis

Degree Name

M.A.Sc.

Department

Mechanical, Automotive, and Materials Engineering

Keywords

Engineering, Mechanical.

Supervisor

McDonald, Thomas W.,

Rights

info:eu-repo/semantics/openAccess

Abstract

Experiments were carried out to investigate the factors which affect the incipient boiling wall superheat for a copper/refrigerant R-123 interface and to compare these results with the behaviour predicted by the Martin-Dominguez nucleation site boiling model. The factors which affect the boiling behaviour of individual nucleation sites as well as the actual surface incipient boiling characteristics such as fluid and system conditions were studied using a facility which produced vertical flow in an annulus between an electrically heated 22.2 mm (0.875 in) outside diameter cooper tube and a 25.4 mm (1 in) internal diameter glass tube. The experimental observations allowed the following conclusions to be drawn: (1) The boiling incipience wall superheat is dependent upon the past thermal history of the surface/fluid interface, decreases as the system pressure increases and is independent of the refrigerant inlet subcooling and its mass flow rate. (2) Each nucleation site is unique and has its own dormancy range between its boiling cessation and its quench wall superheats. A dormant site will resume boiling at the same wall superheat at which it ceased boiling. A quenched site can only reactivate at or above its cessation wall superheat when seeded by vapour from a nearby boiling site. (3) All of these conclusions are compatible with the bubble/cavity model of Martin-Dominguez, a model which provides a very useful tool to explain the often seemingly contradictory results found in the literature.Dept. of Mechanical, Automotive, and Materials Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1997 .L52. Source: Masters Abstracts International, Volume: 37-01, page: 0348. Adviser: Thomas W. McDonald. Thesis (M.A.Sc.)--University of Windsor (Canada), 1997.

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