An experimental and numerical study has been conducted on heat transfer and turbulent flow structure in channels with novel hybrid structures with miniature V-shaped ribs and dimples on one wall. One miniature V-shaped rib was arranged immediately upstream each individual dimple to form the hybrid structure, which aims at inducing additional near-wall secondary flow interacting with the dimple vortex flow and further improving the heat transfer. Steady-state convective heat transfer experiments were done to obtain the heat transfer and pressure loss of the turbulent flow over the surfaces with the miniature V rib-dimples for the Reynolds numbers from 18,700 to 60,000. In addition, the turbulent flow structure in the V rib-dimpled channels has been predicted by carrying out numerical computations. The experimental results indicated that the overall heat transfer enhancement of the miniature V rib-dimpled channels can be increased by up to about 60.0% compared with the counterpart of the dimpled only channel, and by about 23.0% compared with the counterpart of the miniature V ribbed only channel. The miniature V ribs showed appreciable effects on the heat transfer and pressure loss characteristics for the turbulent flow over the V rib-dimpled surfaces. The numerical computations showed that the miniature V rib upstream each dimple produced strong near-wall downwashing secondary flow, which significantly changed the flow patterns and intensified the turbulent flow mixing inside and outside the dimple and above the surrounding wall. These unique near-wall flow characteristics generated a significant heat transfer improvement in both the magnitude and the uniformity.
Heat Transfer and Turbulent Flow Structure in Channels With Miniature V-Shaped Rib-Dimple Hybrid Structures on One Wall
Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received January 2, 2019; final manuscript received April 19, 2019; published online May 17, 2019. Assoc. Editor: Srinath V. Ekkad.
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Zhang, P., Rao, Y., Li, Y., and Weigand, B. (May 17, 2019). "Heat Transfer and Turbulent Flow Structure in Channels With Miniature V-Shaped Rib-Dimple Hybrid Structures on One Wall." ASME. J. Heat Transfer. July 2019; 141(7): 071903. https://doi.org/10.1115/1.4043675
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