Abstract
Internal serpentine ribbed coolant channel with low aspect ratio (AR) has been widely employed to provide excellent thermal protection for advanced first-stage turbine blades. Various height differences (ΔHs) of adjacent passages along pressure side can be generated under the restriction of actual blade profile. The present work made an attempt to acquire detailed influences of ΔH on the time-averaged and transient secondary motions near sharp bends of low-AR coolant channels. An actual blade ribbed three-pass coolant channel with two ΔHs was chosen as experimental model. Planar time-resolved particle image velocimetry technique was applied to capture the transient flow fields in 21 typical cross sections. Time-averaged results were validated by standard PIV measurements and flow visualizations. Snapshot proper orthogonal decomposition was employed to extract the dominant flow structures and identify the underlying small-scale flow patterns in time-resolved velocity fields. The experimental results indicated the low-AR channel with real blade profile induces a new type of the secondary-vortex superposition downstream of bends, in comparison with the large-AR channels in open literature. The crucial reason is the ΔH along pressure side leads to an intensive impingement on the bend wall, which weakens the effects of bend, rib and curvature of suction side. Another new discovery is the effect of ΔH on unsteady internal flow. In the small ΔH case, the oscillatory frequency of the secondary vortices is nearly similar with the counter-rotating Dean-vortices; however, in the large ΔH case, the oscillatory frequency is much lower, and the rotating direction of vortices is same and unchanged in a period. Increasing inlet Reynolds number can significantly change the underlying small-scale flow patterns and improve the oscillatory frequency of large-scale structures, although the basic time-averaged flow patterns are nearly same. Effect of injection from auxiliary-hole (AH) on unsteady internal flow is obvious and the optimum mass flow ratio of AH-to-inlet is 5%.
Graphic Abstract
Similar content being viewed by others
Abbreviations
- AH:
-
Auxiliary-hole
- AR:
-
Aspect ratio
- MFR:
-
Mass flow ratio
- MS:
-
Middle surface
- PIV:
-
Particle image velocimetry
- POD:
-
Proper orthogonal decomposition
- PS:
-
Pressure side
- PSD:
-
Power spectral density
- SS:
-
Suction side
- TKE:
-
Turbulent kinetic energy
- TRPIV:
-
Time-resolved PIV
- ΔΗ :
-
Difference of height
References
Algawair W, Iacovides H, Kounadis D et al (2008) Experimental assessment of the effects of Prandtl number and of a guide vane on the thermal development in a ribbed square-ended U-bend. Exp Therm Fluid Sci 32(2):670–680
Ekkad SV, Pamula G, Shantiniketanam M (2000) Detailed heat transfer measurements inside straight and tapered two-pass channels with rib turbulators. Exp Therm Fluid Sci 22(3):155–163
Elfert M, Jarius MP, Weigand B (2004) Detailed flow investigation using PIV in atypical turbine cooling geometry with ribbed walls. In: Proceedings of the ASME Turbo Expo, GT2004-53566
Falchi M, Romano GP (2009) Evaluation of the performance of high-speed PIV compared to standard PIV in a turbulent jet. Exp Fluids 47:509–526
Fu WL, Wright LM, Han JC (2006) Rotational buoyancy effects on heat transfer in five different aspect-ratio rectangular channels with smooth walls and 45 degree ribbed walls. ASME J Heat Transf 128(11):1130–1141
Funazaki K, Odagiri H, Horiuchi T et al (2018) Detailed studies on the flow field and heat transfer characteristics inside a realistic serpentine cooling channel with a S-shaped inlet. In: Proceedings of the ASME Turbo Expo, GT2018-76225
Gallo M, Astarita T, Carlomagno GM (2012) Thermo-fluid-dynamic analysis of the flow in a rotating channel with a sharp ‘‘U’’ turn. Exp Fluids 53(1):201–219
Han JC (2004) Recent studies in turbine blade cooling. Int J Rotating Mach 10(6):443–457
Han JC (2006) Turbine blade cooling studies at Texas A&M University: 1980–2004. ASME J Thermophys Heat Transf 20(2):161–187
Han JC (2018) Advanced cooling in gas turbines 2016 Max Jakob memorial award paper. ASME J Heat Transf 140:113001-1–11300120
Han JC, Huh M (2010) Recent studies in turbine blade internal cooling. Heat Transf Res 41:803–828
Han JC, Dutta S, Ekkad SV (2001) Gas turbine heat transfer and cooling technology. Taylor & Francis, New York
Kalpakli A, Örlü R, Alfredsson PH (2013) Vortical patterns in turbulent flow downstream a 90° curved pipe at high Womersley numbers. Int J Heat Fluid Flow 44:692–699
Kalpakli A, Örlü R, Alfredsson PH (2015) POD analysis of the turbulent flow downstream a mild and sharp bend. Exp Fluids 56:56–70
LeBlanc C, Ekkad SV, Lambert T et al (2013) Detailed heat transfer distributions in engine similar cooling channels for a turbine rotor blade with different rib orientations. ASME J Turbomach 135(1):011034-1-8–011034-1-8
Liou TM, Chang SW, Chan SP et al (2014) PIV measurements in a two-pass 90-deg ribbed-wall parallelogram channel. In: Proceedings of the ASME Turbo Expo, GT2014-25248
Liou TM, Chang SW, Chan SP et al (2015) Effect of rib angle orientation on flow field in a two-pass parallelogram channel with 180-deg sharp turn. In: Proceedings of the ASME Turbo Expo, GT2015-42684
Liou TM, Chang SW, Huang CY et al (2016) Particle image velocimetry and infrared thermography measurements in a two-pass 90-deg ribbed parallelogram channel. Int J Heat Mass Transf 93:1175–1189
Luo J, Razinsky E (2009) Analysis of turbulent flow in 180 deg turning ducts with and without guide vanes. ASME J Turbomach 131(2):021011-1-10
Mallor F et al (2019) Modal decomposition of flow fields and convective heat transfer maps: an application to wall-proximity square ribs. Exp Therm Fluid Sci 102:517–527
Nakayama H, Hirota M, Fujita H et al (2006) Fluid flow and heat transfer in two-pass smooth rectangular channels with different turn clearances. ASME J Turbomach 128(4):772–785
Poser R, von Wolfersdorf J, Lutum E, et al (2008) Performing heat transfer experiments in blade cooling circuits using a transient technique with thermochromic liquid crystals. In: Proceedings of the ASME Turbo Expo, GT2008-50364
Pu J, Ke Z, Wang J et al (2013) An experimental investigation on fluid flow characteristics in a real coolant channel of LP turbine blade with PIV technique. Exp Therm Fluid Sci 45(2):43–53
Son SY, Kihm KD, Han JC (2002) PIV flow measurements for heat transfer characterization in two-pass square channels with smooth and 90° ribbed walls. Int J Heat Mass Transf 45(24):4809–4822
Town J, Straub D, Black J et al (2018) State-of-the-art cooling technology for a turbine rotor blade. ASME J Turbomach 140:071007-1–07100712
Tunstall R, Laurence D, Prosser R (2016) Large eddy simulation of a T-Junction with upstream elbow: the role of Dean vortices in thermal fatigue. Appl Therm Eng 107(25):672–680
Tyagi M, Acharya S (2005) Large eddy simulations of flow and heat transfer in rotating ribbed duct flows. ASME J Turbomach 127:486–498
Wang P, Pu J, Yu R, et al (2018) An experimental investigation on internal flow characteristics in a realistic and entire coolant channel with ribs and film holes. In: Proceedings of ASME Turbo Expo, GT2018-75715
Wen X, Liu YZ, Tang H (2018) Near-field interaction of an inclined jet with a crossflow: LIF visualization and TR-PIV measurement. J Vis 21:19–38
Yu R, Pu J, Wang P et al (2019) Auxiliary hole influence on internal flow characteristics in bend region of a real investment-casting blade coolant channel. Exp Therm Fluid Sci 102(4):123–136
Acknowledgments
The authors are grateful to Mr. Shu-Min Xu for his guidance in the TRPIV application. Funding was provided by Commercial Aircraft Engine Co., Ltd. of Aero Engine Corporation of China.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Pu, J., Yu, Rb., Wang, Jh. et al. POD analysis of passage-layout effect on unsteady internal flow in a realistic blade serpentine coolant channel with low aspect ratios. J Vis 23, 805–823 (2020). https://doi.org/10.1007/s12650-020-00669-4
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12650-020-00669-4