Abstract
This paper focuses on the internal flow development of an S-shaped diffusing duct. Based on the experimental result of total pressure recovery coefficient, the Reynolds stress model (RSM) was selected as a suitable turbulence model for the present study. The numerical results show that 6.2 times the area ratio of the exit to inlet and the aggressive deflection at the first bend of the lower wall lead to strong adverse pressure gradient and very large flow separation, and create a pair of counter-rotating vortices along streamwise direction. The duct diffuser efficiency is 72.37 %. The area-averaged total pressure recovery coefficient at the exit of the duct is 0.9814, and the synthesis distortion index DC (60) is 0.7081.
Funding statement: Natural Science Foundation of China, Funder Id: , Grant Number: No. 51576124
Nomenclature
- p
-
Static pressure
- p*
-
Total pressure
-
-
Total pressure recovery coefficient
- Cp
-
Pressure rise coefficient
- AR
-
Area ratio of exit to inlet
-
-
Diffuser efficiency
Acknowledgements
This work is supported by the Natural Science Foundation of China (No. 51576124), and the United Innovation Center (UIC) of Aerothermal Technologies for Turbomachinery.
References
1. Marn A, Gottlich E, Pecnik R, Malzacher FJ, Schennach O, Pirker HP. The influence of blade tip gap variation on the flow through an aggressive S-shaped intermediate turbine duct downstream a transonic turbine stage: part I—time-averaged results. ASME Turbo Expo 2007: Power for Land, Sea, and Air, 2007.Search in Google Scholar
2. Gräsel J, Pierré M, Demolis J. Parametric interturbine duct design and optimisation. Int Congr Aeronaut Sci (ICAS). ICAS 2006-5.1.2, 2006.Search in Google Scholar
3. Jin D, Liu X, Zhao W, Gui X. Optimization of endwall contouring in axial compressor S-shaped ducts. Chin J Aeronaut. 2015;28:1076–86.10.1016/j.cja.2015.06.011Search in Google Scholar
4. Garnier E, Leplat M, Monnier JC, Delva J. Flow control by pulsed jet in a highly bended S-duct. 6th AIAA Flow Control Conference, AIAA-2012-3250, 2012.10.2514/6.2012-3250Search in Google Scholar
5. Garnier E. Flow control by pulsed jet in a curved S-duct: a spectral analysis. Aiaa J. 2015;53:2813–27.10.2514/1.J053422Search in Google Scholar
6. Du L, Liu Y, Li T. Numerical predictions of scarfing on performance of S-shaped nozzle with asymmetric lobe. J Propul Power. 2014;31:604–18.10.2514/1.B35222Search in Google Scholar
7. Göttlich E. Research on the aerodynamics of intermediate turbine diffusers. Prog Aerosp Sci. 2011;47:249–79.10.1016/j.paerosci.2011.01.002Search in Google Scholar
8. Wellborn SR, Reichert BA, Okiishi TH. Study of the compressible flow in a diffusing S-duct. J Propul Power. 1994;10:668–75.10.2514/3.23778Search in Google Scholar
9. Yu CM. 1991. Flow characteristics in S-shaped diffusing ducts, Ph.D. thesis, Imperial College London (University of London).Search in Google Scholar
10. Whitelaw JH, Yu S. Velocity measurements in an S-shaped diffusing duct. Exp Fluids. 1993;15:364–7.10.1007/BF00223414Search in Google Scholar
11. Lee BJ, Kim C. Automated design methodology of turbulent internal flow using discrete adjoint formulation. Aerosp Sci Technol. 2007;11:163–73.10.1016/j.ast.2006.12.001Search in Google Scholar
12. Gerolymos GA, Joly S, Mallet M, Vallet I. Reynolds-stress model flow prediction in aircraft-engine intake double-S-shaped duct. J Aircr. 2010;47:1368–81.10.2514/1.47538Search in Google Scholar
13. Fiola C, Agarwal RK. Simulation of secondary and separated flow in diffusing S ducts. J Propul Power. 2010;31:180–91.10.2514/6.2014-0561Search in Google Scholar
14. Bu H, Tan H, Chen H, He X. Investigation on secondary flow characteristics in a curved annular duct with struts. Flow Turbul and Combust. 2016;97:27–44.10.1007/s10494-015-9674-5Search in Google Scholar
15. Watson RA, Tucker PG, Menzies K. Unsteady simulations of the wellborn diffusing S-duct. 54th AIAA Aerospace Sciences Meeting, AIAA 2016-2126, 201610.2514/6.2016-2126Search in Google Scholar
16. Asghar A, Stowe RA, Allan WD, Alexander D. Entrance aspect ratio effect on S-duct inlet performance at high-subsonic flow. ASME Turbo Expo 2016: Turbomachinery Technical Conference and Exposition, GT2016–57875, 2016.10.1115/GT2016-57875Search in Google Scholar
17. Asghar A, Stowe RA, Allan WD, Alexander D. Performance evaluation of an S-duct diffuser of a flight-vehicle inlet in high-subsonic flow, ASME Turbo Expo 2015: Turbine Technical Conference and Exposition, GT2015–43740, 2015.10.1115/GT2015-43740Search in Google Scholar
18. Denton JD. Some limitations of turbomachinery CFD, ASME Paper No. GT2010–22540, 2010. DOI: 10.1115/GT2010-22540. Search in Google Scholar
19. Gottschall M, Vogeler K, Mailach R, The effect of four part gap geometry configurations for variable stator vanes in a compressor cascade, ASME Paper No. GT2012–69757, 2012. DOI: 10.1115/GT2012-69757.Search in Google Scholar
20. Marty J, Aupoix B. Interaction of shrouded stator flow and main flow and its influence on performances of a three-stage high pressure compressor, part A. J Power Energy. 2012;226:489–500. DOI: 10.1177/0957650911414322.Search in Google Scholar
21. Wang F, Carnevale M, Mare L, Gallimore S. Simulation of multistage compressor at off-design conditions. J Turbomach. 2018;140:021011. DOI: 10.1115/1.4038317.Search in Google Scholar
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