Record Details
Motion picture study of a vertical climbing film in an annular duct
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Motion picture study of a vertical climbing film in an annular duct |
| Names |
Scott, Bruce Douglas
(creator) Knudsen, James G. (advisor) |
| Date Issued | 1969-03-19 (iso8601) |
| Note | Graduation date: 1969 |
| Abstract | This paper describes a study of two-phase gas-liquid vertical annular climbing film flow. Using a high speed Fastax movie camera, motion was slowed sufficiently to facilitate detailed analysis of the climbing film structure, based on single frame projections. The dynamic characteristics of the liquid film could likewise be obtained, though these were necessarily of a qualitative nature, A technique based on a diffusion controlled electrochemical reaction was employed to monitor the local instantaneous mass transfer coefficient at the solid-liquid interface. The resultant fluctuating electrical signal was amplified and presented for direct comparison with the climbing film structure, using split image photography. The signal was also subjected to a spectral density analysis to further understanding of the nature of the turbulence produced at the interface. The vertical annular column was constructed of a three-inch inside diameter clear plexiglass tube, with a one-inch outside diameter concentric core, supported laterally by a series of streamlined centering pins. The column extended some 35 feet from the base with all tests carried out approximately midway up the column to minimize end effects. The particular construction of the column permitted an unobstructed view of the free surface of the climbing film. Determination of the pressure gradients was likewise simplified as the inner surface of the outer tube remained essentially dry throughout the experimental program. The air flow rates varied from 172 cfm to 616 cfm at one atmosphere pressure and 68°F, temperature. Liquid flow rates were confined to a range from .19 lbm/min to 1.5 lbm/min so as to stay within the climbing film regime. From the movie film analysis, values for the average film thickness, wave frequency and phase velocity were determined with their respective standard deviations. Two empirical models have been proposed which fit the average film thickness data to within 6%. The film thickness results were also compared with the values predicted by several mathematical models, two of which were based on a modification of Kapitza's original theory. |
| Genre | Thesis/Dissertation |
| Topic | Two-phase flow |
| Identifier | http://hdl.handle.net/1957/46543 |
