الفهرس 
English AbstractOnly 14 pages are availabe for public view
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Abstract
Convective heat transfer between two co-axially horizontal cylinders with heated inner cylinder is studied numerically and investigated experimentally. The effect of cylinders rotational speed (Rotational Reynolds number), inlet velocity to annulus (Axial Reynolds number) and radius ratio are investigated. The numerical study is carried out using CFD (Computational Fluid Dynamics) code. ANSYS Workbench Release 15.0 is set up to solve three-dimensional laminar fluid flow and heat transfer in annulus using ANSYS FLUENT. Air with 0.7 Prandtl number is considered as working fluid. The inner cylinder of (0.05 m) in diameter, (0.5 m) in length, is subjected to constant heat flux (600 w/m2). While, the outer cylinder of (0.1 m) in diameter, (0.5 m) in length is set as adiabatic wall. The effect of the axial Reynolds number (ranges between 340 - 1700), the inner cylinder rotational speed (ranges between 0 - 600 rpm), the outer cylinder rotational speed (ranges between 0 - 600 rpm) and effect of outer / inner radius ratio on velocity distributions, temperature profiles and in turn, on heat transfer process in the horizontal annulus are studied. Local and average Nusselt number and skin friction coefficient are obtained. The experimental investigation is conducted for the laminar heat transfer in an annular channel between two concentric cylinders with heated inner cylinder (constant heat flux) and adiabatic stationary outer cylinder. The experimental results are obtained for an inlet air velocity range of 0.4, 0.6, 0.7 m/s, for a wall heat flux range of 160–600W/m2 and inner cylinder rotational speed ranges from 0 to 600 rpm. Finally, the relationships between the local, average Nusselt number and the effective Reynolds number for experimental results are proposed and compared with those in the existing literature.