Predictions of flow and heat transfer in sharp 180-deg turns of gas turbine coolant channels with and without turning vanes
A numerical study was conducted to determine the effects of turning vanes on the flow characteristics, the pressure drop and the heat transfer distribution in the turn region of two-legged, coolant passages for application to cooling gas turbine blades. The channels consisted of two straight, square-sectioned legs connected by a 180-deg. turn, with an inner radius of 0.15 hydraulic diameters. The ribs were square-sectioned with a height of 0.1 D{sub h}, staggered between leading and trailing side and at an angle of 45-deg. to the flow. Three different configurations of the coolant channel were investigated: with smooth walls, with ribs on two walls and no vane and with ribs on two walls and a 180-deg guide vane in the turn. For all calculations, the Reynolds number at the inlet was Re{sub D} = 100,000, the fluid was water and buoyancy effects were neglected. The simulations were made for rotation numbers, Ro = 0.0 and 0.15. The flow and heat transfer simulations were made with the FLUENT structured code. Based on the results of several previous studies, the differential-Reynolds-Stress turbulence model with wall functions was used. The highest heat transfer in the turn was obtained for both the rotating and non-rotating cases with the ribbed channel without the guide vane. The pressure loss was also higher without the vane. Due to the staggering of the ribs, secondary flow and heat transfer in the turn was higher on the side of the channel where the last rib at the entrance reaches further into the turn. With increasing rotation number, the secondary flow and heat transfer increased on the leading side of the turn. For the configuration with a 180-deg. vane, the mass flux at the outer side of the vane increased with increasing rotation number.
- Research Organization:
- ABB Corporate Research Ltd., Baden-Daettwil (CH)
- OSTI ID:
- 20002440
- Report Number(s):
- CONF-990805-; TRN: IM200002%%440
- Resource Relation:
- Conference: 33rd National Heat Transfer Conference NHTC'99, Albuquerque, NM (US), 08/15/1999--08/17/1999; Other Information: PBD: 1999; Related Information: In: Proceedings of the 33rd national heat transfer conference NHTC'99, by Jensen, M.K.; Di Marzo, M. [eds.], [1150] pages.
- Country of Publication:
- United States
- Language:
- English
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