الفهرس 
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Abstract
Dissertation Abstract thesis deals with cooling of protruding heat sources as a modeling of cooling of electronic equipments. Experimental and numerical investigations are conducted to study the heat transfer enhancement in electronic components by re-directing the air flow to the surfaces of the heat sources and cavities between them. The numerical investigation is conducted using a commercial package “FLUENT 6.1”. The study simulates the electronic components as a three heat sources which are mounted in a horizontal rectangular channel. The flow is re-directed to the heat sources using three inclined obstacles above the heat sources in order to orient the flow to both the closed cavity regions and heat sources surfaces. The heat sources dimensions are 15 cm width, 4 cm length, and 2 cm height with a spacing equals the heat source length, and channel heights of 9, 8.2, 7.4, 6.6, and 5.8 cm while the obstacles inclination angles are 26.5o, 36.9o, 45o, and 51.3o. The Reynolds number, based on the heat source length, is ranged from 856 to 8340 and Grashof number is fixed at approximately 2.0 x 107 . The study is extended to investigate the effect of channel height, at fixed inclined obstacle angle of 36.9o, on heat transfer characteristics while the heat sources height is constant. This leads to height ratios (HR) of 0.222, 0.244, 0.27, 0.303, and 0.345. The pressure DROP due to heat sources protrusion and the inclined obstacles is also investigated. The results show that, as obstacle angle increases or channel height decreases (height ratio increases) the heat transfer for the three heat sources increases and gives an enhancement in the average Nusselt number up to 153.4%. It is noticed that, as the obstacle inclination angle increases the second heat source towards to have the highest heat transfer coefficient. As obstacle angle or height ratio increases, the pressure DROP increases sharply. So, when using the inclined obstacles, an optimization is needed between heat transfer enhancement and pressure drop. Two empirical correlations for average Nusselt number as a function of Richardson number and obstacle inclination angle or height ratio are obtained for each heat source. Key words: Cooling - Protruding - Heat – Mixed convection