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Flow patterns and heat transfer mechanism of circular closed thermosyphons

Journal Article · · Heat Transfer - Japanese Research; (USA)
OSTI ID:5806653
;  [1]; ;  [2];  [3]
  1. Muroran Inst. of Technology (JP)
  2. Faculty of Engineering, Hokkaido Univ. (JP)
  3. Hokkaido Matsushita Electric Co. Ltd. (JP)
+ Show Author Affiliations
Measurements of the heat transfer and the flow visualization were carried out on vertical closed and open thermosyphons using water and ethylene glycol as working fluids. The sizes of the closed thermosyphons were 10 and 20 mm in radius and 300 mm in length, and that of the open thermosyphon was 20 mm in radius and 150 mm in length. The present Nusselt number and flow pattern of the closed thermosyphons are compared with those of the open thermosyphon and the experimental and theoretical Nusselt numbers of the closed thermosyphon by Bayley et al. The Nusselt number of the closed thermosyphons significantly decreases for the predominant flow of the conduction mode and the weak flow of the convection mode in the coupling region. The fraction of the flow of the convection mode is usually small and sensitively varied with the change of the tube diameter and the Rayleigh number for the range of diameters form 20 to 50 mm.
OSTI ID:
5806653
Journal Information:
Heat Transfer - Japanese Research; (USA), Journal Name: Heat Transfer - Japanese Research; (USA) Vol. 18:6; ISSN 0096-0802; ISSN HTJPA
Country of Publication:
United States
Language:
English

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Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320303 -- Energy Conservation
Consumption
& Utilization-- Industrial & Agricultural Processes-- Equipment & Processes
42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
ALCOHOLS
DATA
DESIGN
ENERGY TRANSFER
EXPERIMENTAL DATA
FLOW VISUALIZATION
GLYCOLS
HEAT TRANSFER
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
INFORMATION
NUMERICAL DATA
NUSSELT NUMBER
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OXYGEN COMPOUNDS
POLYETHYLENE GLYCOLS
POLYMERS
THEORETICAL DATA
THERMOSYPHONS
WATER