Bubble nucleation at subcooled flow boiling condition in a horizontal annular channel with a square cross section by the use of high-speed camera is investigated. The channel represents a scaled-down version of a single rod of CANDU reactor core. The experiments were performed by the use of water at pressures between 1-3 atm, constant heat flux of 0.124 MW/m2, liquid bulk subcooling of 32-1oC and mean flow velocities of 0.3-0.4 m/s. Bubble lift-off diameters were obtained from direct high speed videography. The developed model for the bubble lift-off diameter was obtained by analyzing the forces acting on a bubble. Furthermore, a model for the bubble growth rate constant was suggested. The proposed model was then compared to experimental data and it has shown a good agreement with the experimental data. Additionally, the effects of liquid bulk subcooling, liquid pressure and mean flow velocity on bubble lift-off diameter were investigated.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/42917 |
| Date | 27 November 2013 |
| Creators | Shaban Nejad, Saman |
| Contributors | Nasser, Ashgriz |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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