Simultaneous hydrodynamic and thermal development in mixed convection in a vertical annulus with fluid property variations

Journal Article · Fri Nov 01 04:00:00 EST 1991 · Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States)

DOI:https://doi.org/10.1115/1.2911223· OSTI ID:7271546

Aung, W; Moghadam, H E ^[1]; Tsou, F K ^[2]

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1. Howard Univ., Washington, DC (United States)
2. Drexel Univ., Philadelphia, PA (United States)

This paper concerns a theoretical investigation of forced and mixed convection heat transfer in a vertical concentric annulus. An implicit finite difference technique is developed to study the effects of temperature-dependent fluid properties, which are represented by power law relations. The fluid under consideration in this study is air, which is an ideal gas with Pr = 0.72. Computations are made with a radius ratio of 0.25. The inner wall is heated at UHF, and the outer wall is heated at UHF or is insulated. The axial distribution of the wall-to-bulk temperature ratio is found to undergo a maximum or minimum, depending on whether the wall is heated or insulated. Fluid property variations enhance the local Nusselt numbers. It is shown that, depending on the length of the duct, heat transfer can be appreciably affected by fluid property variation. For the UHF cases studied here, free convection effects enhance the local Nusselt numbers at intermediate axial distances.

• OSTI ID: 7271546
• Journal Information: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States), Journal Name: Journal of Heat Transfer (Transactions of the ASME (American Society of Mechanical Engineers), Series C); (United States) Vol. 113:4; ISSN 0022-1481; ISSN JHTRA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
AIR
ANNULAR SPACE
CONFIGURATION
CONVECTION
ENERGY TRANSFER
FLUIDS
FORCED CONVECTION
GASES
HEAT TRANSFER
MASS TRANSFER
NATURAL CONVECTION
NUSSELT NUMBER
ORIENTATION
PHYSICAL PROPERTIES
SPACE
TEMPERATURE DEPENDENCE