Flow and heat transfer characteristics of NACA vortex generator with curved-divergent walls are numerically studied and the corresponding heat transfer enhancement mechanism is also analyzed by local streamlines, velocity vector diagram and velocity contour diagram. The variation of vortices at different positions along the flow direction is also illustrated. The impacts of the width W and height H on the heat transfer as well as pressure loss are investigated with Re ranging from 3602 to 9004. Additionally, both Nu and ?P are considered when evaluating the comprehensive performance. The results show that as the width and height increase, the average Nu and ?P increase as well. Compared with the channel without the NACA vortex generator, the average Nu and ?P increased by about 7.3% and about 3.6%, respectively, by W=30 mm; the average Nu and ?P increased by about 7.6% and about 4.5%, respectively, by H=10 mm. The variation of comprehensive performance shows an opposite trend. The ? obtained the largest value of about 1.042 and 1.04 in the case of W=10 mm and H=4 mm, respectively. Additionally, the variation of the local Nu is similar to that of the Y-vorticity.

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