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ISSN Online: 2377-424X

ISBN Print: 0-89116-559-2

International Heat Transfer Conference 8
August, 17-22, 1986, San Francisco, USA

OSCILLATION PHENOMENA AND OPERATING LIMITS OF THE CLOSED TWO-PHASE THERMOSYPHON

Get access (open in a dialog) DOI: 10.1615/IHTC8.4690
pages 2325-2330

要約

In a vertical thermosyphon an up-going vapor flow prevents a liquid film from flowing downward and causes flooding if the heat input exceeds a certain value. Then the evaporator wall partially dries out. The wall temperature in the evaporator and the system pressure are measured and their post-dryout behavior is classified into three types:(1) the periodic oscillation, and transient variations going asymptotically to (2) the higher and (3) the lower than the initial system pressure setting. The occurrence of the first type, periodic oscillation, is limited to when the amount of working fluid, methanol, is about one-third of the evaporator volume. To explain these changes in the system pressure and wall temperature a physical model, based on the alternating flooding and deflooding concept, is proposed.
In this work the effects of tube diameter, amount of working fluid, and system pressure on these oscillations and the flow and heat transfer characteristics during the oscillations are also experimentally investigated.