This thesis presents the developmental, practical and theoretical aspects of an improved Berthelot tube apparatus used to investigate cavitation phenomena in deionised water. Values of the breaking tension of deionised water in the range of 2.5 bar to 30 bar are herein reported for experiments in the improved apparatus and the obtained breaking tensions are certainly comparable to those previously reported for experiments carried out using both the Berthelot tube technique and other methods. Herein dynamic pressure records and high-speed photographic images of cavitation occurring in deionised water are reported, for what is believed to be the first time. The initial formation, growth and collapse of cavitation bubbles are compared to the dynamic pressures existing in the tube using analytical methods to process the high-speed images and dynamic pressure traces. The growth/collapse cycles of bubbles associated with cavitation in the improved apparatus are shown to be an order of magnitude higher than those occurring in bullet-piston experiments (a typical cycle taking about 240 μs in the improved Berthelot tube), and the corresponding velocity of the initial growth of the cavity is reported to be in the order of 21 m/s. In Chapter 6 high-speed images of the formation of ice in deionised water under double metastable conditions are reported for the first time. In these experiments it was shown that it was possible for deionised water in a double metastable phase to be cooled to -18°C before ice suddenly started to form, at a specific point, and rapidly propagated throughout the water at a much greater rate (upwards of 25 cm/s) than would otherwise be predicted for the formation of ice under ‘free’ conditions, suggesting that some additional factor was involved in the ice formation. Several proposals have been put forward in an attempt to explain the mechanism behind the ice formation.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:638705 |
| Date | January 2005 |
| Creators | Rogers, D. |
| Publisher | Swansea University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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