TY - JOUR ID - TI - EXPERIMENTALAND THEORETICAL STUDY OF NATURAL CONVECTION HEAT TRANSFER OFHEATED SQUARE CYLINDER PLACED INSIDE A COOLED CIRCULAR ENCLOSURE FILLED WITH AIR AU - Laith Ayad Salman, and Abdul jabbarJwairShamikh PY - 2012 VL - 12 IS - 3 SP - 564 EP - 581 JO - Iraqi journal of mechanical and material engineering المجلة العراقية للهندسة الميكانيكية وهندسة المواد SN - 20761819 AB - In this paper, an experimental and theoretical study of natural convection heat transfer in a closed ends annulus region formed by a heated square cylinder placedconcentrically in a larger isothermally cooled circular cylinder. Experiments arecarried out for Rayleigh number based on the equivalent annulus gap length rangesfrom 103 up to 106. Different aspect ratios, 0.2 up to 0.5, are considered. Thenumerical simulation for the problem is carried out by using commercial CFD code(FLUENT 6.3).The average Nusselt number from the experimental results iscompared with that obtained from the CFD code. The fluid flow and heat transfercharacteristics for different operating and geometric conditions are illustrated throughstream lines and isotherms contours that obtained from the CFD code. The resultsshowed thatas the aspect ratio increases the heat transfer rateand the average Nusseltnumber increase. Also the result showed that as Rayleigh number increases theaverage Nusselt number increases.

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