Influence of Dimple Shapes on Turbulent Flow and Heat Transfer

Abstract

Abstract:

Abstract： Dimples are very effective structures to enhance heat transfer. Based on numerical simulations, this paper investigated the heat transfer and friction factor of sphere, eliptical, inclined eliptical and teardrop dimple. Comparisons of the heat transfer and friction factor results obtained by using the Relizable k-ε, SST, and Standard k-ω models with the experimental results indicate that the Standard k-ω model can best predict the flow and heat transfer in the dimpled channels. The heat transfer and flow structure characteristics in the four dimpled channels have been obtained and compared with each other for the Reynolds numbers of 8 500 to 60 000.The Matlab software is used in this paper to process the numerical data to get the heat transfer distribution along the streamwise direction. The study shows that compared to the flat channel, the sphere dimple enhances the heat transfer by 40% and the friction factor by 70%; the eliptical dimple enhances the heat transfer by 30% and the friction factor by 60%;the inclined eliptical dimple enhances the heat transfer by 40% and the friction factor by 60%; and the teardrop dimple enhances the heat transfer by 70% and the friction factor by 100%. Generally speaking, the teardrop dimple has the best heat transfer and overall performance.

Key words: dimple, vortex generator, gas turbine cooling, heat transfer, friction factor

CLC Number:

TK 47

FENG Yan,RAO Yu,LI Bo. Influence of Dimple Shapes on Turbulent Flow and Heat Transfer[J]. Journal of Shanghai Jiaotong University, 2015, 49(05): 614-619.

References

［1］Han J C, Dutta S, Ekkad S. Gas turbine heat transfer and cooling technology［M］. England: Taylor and Francis, 2001.

［2］Rao Y, Zang S S. Flow and heat transfer characteristics in latticework cooling channels with dimple vortex generators［J］. ASME J Heat Transfer, 2014,136 (2): 0210170210110.

［3］张翔，饶宇. 具有凹陷涡发生器的网格冷却结构内的流动和传热特性［J］. 航空动力学报，2013, 28（17）：15031509.

ZHANG Xiang, RAO Yu. Flow and heat transfer characteristics in latticework cooling structure with dimple vortex generators［J］. Journal of Aerospace Power, 2013, 28(17):15031509.

［4］Chyu M K, Yu Y, Ding H, et al. Concavity enhanced heat transfer in an internal cooling passage［C］∥International Gas Turbine and Aeroengine Congress and Exhibition. USA: ASME, 1997: V003T09A08087.

［5］Burgess N K, Ligrani P M. Effects of dimple depth on channel Nusselt numbers and friction factors［J］. ASME Journal Heat Transfer, 2005, 127(8): 839847.

［6］Ligrani P M, Harrison J L, Mahmood G I, et al. Flow structure due to dimple depression on a channel surface［J］. Physics Fluids, 2001, 13 (11): 34423451.

［7］Johann T, Nikolai K, Valery Z, et al. Flow structures and heat transfer on dimples in a staggered arrangement［J］. International Journal of Heat and Fluid Flow, 2012, 35 (1): 168175.

［8］Kim H M, Moon M A, Kim K Y. Multiobjective optimization of a cooling channel with staggered elliptic dimples［J］. Energy, 2011, 36 (5): 34193428

［9］Bunker R S, Donnellan K F. Heat transfer and friction factors for flows inside circular tubes with concavity surfaces［J］. ASME Journal of Turbomachinery, 200, 125 (4): 665672.

［10］Rao Y, Wan C, Zang S. An experimental and numerical study of the flow and heat transfer in channels with pin findimple combined arrays of different configurations［J］. ASME J Heat Transfer, 2012, 134 (12): 121901.

［11］Gee D L, Webb R L. Forced convection heat transfer in helically ribroughened tubes［J］. International Journal of Heat Mass Transfer, 1980, 23(8): 11271136.

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