Natural convection in vertical annuli: A numerical study for constant heat flux on the inner wall

Journal Article · Wed Nov 01 00:00:00 EST 1989 · Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States)

DOI:https://doi.org/10.1115/1.3250805· OSTI ID:6104904

Khan, J A; Kumar, R ^[1]

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1. Clemson Univ., SC (United States)

A numerical investigation has been conducted to evaluate the effects of diameter ratio and aspect ratio in natural convection of gases within vertical annuli. The inner cylinder is maintained at uniform heat flux and the outer cylinder at constant temperature. The horizontal top and bottom walls are insulated. Detailed result of {le} 15, 1 {le} A {le} 10, and 100 < Ra{sub L}* < 10{sup 7}. The inner wall temperature is a function of diameter ratio and aspect ratio. The heat transfer results have been compared with those for isothermal heating, and have been found to be higher. The inner wall temperature is a function of diameter ratio and aspect ratio. The heat transfer results have been compared with those for isothermal heating, and have been found to be higher. The inner diameter is seen to be the appropriate length scale for high Rayleigh number flows and/or high radius ratios, and the radius ratio effect on heat transfer is seen to be insignificant for radius ratios greater than 10. The heat transfer results based on the inner diameter are in very good agreement with published experimental results, although these experiments were conducted for very high aspect ratio. Heat transfer correlations are provided.

• OSTI ID: 6104904
• Journal Information: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States), Vol. 111:4; ISSN 0022-1481
• Country of Publication: United States
• Language: English

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