Natural convection in an annulus between two isothermal concentric square ducts
Natural convection heat transfer and fluid flow in the annulus between two concentric cylinders and spheres have received considerable attention from many researchers because of their important applications in physics and engineering. Some of the examples are nuclear reactor design, thermal energy storage cells that utilize phase transitions, solar energy collectors and many other practical situations. This paper is focused on steady-state, laminar, two-dimensional natural convection in an annulus between two isothermal concentric square ducts. Stream function-vorticity formulation was applied and control volume integration solution technique is adopted in this study. Solutions are obtained up to Rayleigh number of 10{sup 6}. Three different dimension ratios, L*, namely 1/5, 3/10 and 3/5, are considered. The effects of dimension ratio and Rayleigh number on the flow structure and heat transfer are investigated. The results show that dimension ratio and Rayleigh number have a profound influence on the temperature and flow field. As the dimension ratio is increased (decreasing the gap between squares), a multiple cell solution is developed between the upper sides of the square ducts. The transition to the multiple cell solution depends on the Rayleigh number, Ra and dimension ratio L*. The results of heat transfer are also presented and comparisons with earlier experimental results are made.
- Research Organization:
- Karadeniz Technical Univ., Trabzon (TR)
- OSTI ID:
- 20030400
- Journal Information:
- International Communications in Heat and Mass Transfer, Journal Name: International Communications in Heat and Mass Transfer Journal Issue: 3 Vol. 27; ISSN 0735-1933; ISSN IHMTDL
- Country of Publication:
- United States
- Language:
- English
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