Experimental Study of Forced Convection in a Rectangle Ductwith Cross-Ribs on the Opposite Walls
Deng Bin¹,T.T.Wong²,Tao Wenquan¹
(1.School of Energy and Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China; 2.Department of Mechanical Engineering, The Hong Kong Polytechnic University)

Abstract：Within the Reynolds number range from 5000 to 40000, experiments were performed by using cross-ribs (three angles:45,60,75 degrees;two heights: 4mm, 5mm) roughened ducts to determine the effect of building repeated turbulators of the inner surface of the rectangular duct on forced convection and fluid fricton. The experimental results show that for the cross rib arrangements studied, the rib height and cross angle have positive effect on heat transfer; the larger the cross angles and the rib height, the higher the heat transfer coefficients. At the meantime, the friction factor also increases significantly. Compared with the parallel rib configuration, the cross-rib arrangement can enhance heat transfer with greater penalty in pressure drop.
Keywords：cross-ribs;forced convection;heat transfer enhancement