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Augmented Heat Transfer in Square Duct with 90° Arc of Circle and V Shape Rib


Laxmikant Jadhav , SIRT, BHOPAL, MP; Prof. Richard Victor, SIRT, BHOPAL , MP


Heat Transfer Enhancement, 90° Arc of Circle Rib, V Shape of Circle RIB, Augmentation, Square Channel, Nusselt Number


In the advanced gas turbines of today, the turbine inlet temperature can be as high as 1500°C; however, this temperature exceeds the melting temperature of the metal airfoils. Therefore, it is imperative that the blades and vanes are cooled, so they can withstand these extreme temperatures. Cooling air around 650°C is extracted from the compressor and passes through the airfoils. With the hot gases and cooling air, the temperature of the blades can be lowered to approximately 1000°C, which is permissible for reliable operation of the engine. In order to avoid premature failure, designers must accurately predict the local heat transfer coefficients and local airfoil metal temperatures. By preventing local hot spots, the life of the turbine blades and vanes will increase. In the diameter present work, the effect of the rib angle orientation on the local heat transfer distribution and pressure drop in a square channel with two opposite in- line ribbed walls was investigated for Reynolds numbers from 45000 to 75000. The objective of the present work is to study the effect of rib height to the hydraulic ratio (e/Dh) on the local heat transfer distributions and flow friction in ribbed square channel with 90° arc of circle rib and V shape of circle ribs. Rib geometries, comprising three rib height-to-channel hydraulic diameters (blockage ratio) of 4.482, 6.75, and 9.018 as well as rib spacing (pitch to height ratio) is 10. A square channel, roughened with different blockage ratio ribs on two opposite walls in in-line manner and perpendicular to flow direction was tested. An experimental result shows that 90 degree arc of circle rib has maximum HTC as compared to V shape of circle rib with maximum pressure drop penalty It is observed that the heat transfer augmentations in the channel with 90° arc of circle attached ribs increase with increase in the rib height to hydraulic diameter ratio (e/Dh) but only at the cost of the pressure drop across the test section.

Other Details

Paper ID: IJSRDV7I10014
Published in: Volume : 7, Issue : 1
Publication Date: 01/04/2019
Page(s): 6-9

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