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1

Thermal radiation effects on free convection over a rotating axisymmetric body with application to a rotating hemisphere

Hossain M. A., Anghel M., Pop I.

Archives of Mechanics

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2002

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Vol. 54, nr 1

55-74

EN

This paper deals with the interaction of thermal radiation with free convection, laminar boundary-layer flow past a heated rotating axisymmetric round-nosed body of uniform surface temperature. The fluid considered is a gray, absorbing-emitting but nonscattering medium, and Rosseland approximation is used to describe the radiative heat flux. The difficulty of having a unified mathematical treatment of this problem is due to the nonsimilarity nature of the governing equations arising from the buoyant force-field and the transverse curvature of the body. The important parameters of this problem are the Planck number, Rd, the buoyancy parameter, ..., and the wall to free stream temperature ratio, .... Numerical solution of the boundary-layer equations are performed using the Keller-box method as well as the local nonsimilarity method. The theory is applied to a rotating hemisphere for a gas with Prandtl number of 0.72. The effects of the parameters ..., Rd and ... are shown on the velocity and temperature profiles, as well as on the local skin friction coefficient and local rate of heat transfer.

2

Combined heat and mass transfer by free convection past an inclined flat plate

Anghel M., Hossain M. A., Zeb. S., Pop I.

International Journal of Applied Mechanics and Engineering

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2001

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Vol. 6, no 2

473-487

EN

The steady laminar free convection boundary layer over the upper surface of a semi-infinite flat plate which is inclined at a small angle to the horizontal under the combined buoyancy effects of thermal and mass (concentration) effects is theoretically studied in this paper. Series solutions are obtained for both positive and negative inclinations of the plate, valid near the leading edge of the plate. Also, a series solution, which is valid only for positive inclinations and far downstream from the leading edge of the plate, is determined. The Keller-box scheme is then used to complete the solution in the regions where neither series is adequate using the full boundary layer equations. Results for the skin friction coefficient, the local Nusselt and Scherwood numbers are presented. Also, the variation of the separation point of the boundary layer with the Schmidt number is determined and shown on a graph.

3

Combined heat and mass transfer by mixed convection flow over a horizontal plate

Anghel M., Pop I.

Applied Mechanics and Engineering

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1999

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Vol. 4, no 4

773-788

EN

This paper studies combined heat and mass transfer by laminar mixed convection over a horizontal plate with uniform wall temperature and concentration. Numerical solutions of the nonsimilar boundary layer equations governing the flow, energy and concentration are obtained by employing an implicit finite-difference approximation together with the Kelley box method. Distribution of the velocity, temperature and concentration profiles as well as of the local Nusselt and Sherwood numbers are calculated. The flow characteristics are revealed to be significantly influenced by the buoyancy ratio parameter, mixed convection parameter and Schmidt number.