Modares Mechanical Engineering

Modares Mechanical Engineering

Numerical investigation of airfoil geometric variations impacts on flow structures in a subsonic fan using Large Eddy Simulation method

Authors
Mahmood Asgari Savadjani 1
Behzad Ghadiri 2
1 Tarbiat Modares University-PhD Candidate
2 Tarbiat Modares University
Abstract
The numerical simulation of near-stall condition in a passage of an isolated subsonic rotor is studied in detail. The requirements of numerical simulation in order to resolve turbulent spectra around the blade are studied. According to the fact that most of unsteady aerodynamic phenomena incept from blades leading edge, and the role of this part in types and intensity of instabilities, the goal of this paper is to investigate the effects of changes in radius of leading edge of airfoil on flow phenomena in different scales of wave numbers. The governing equations of flow-field are solved using different numerical approaches. Resolution characteristics of different modeling and simulation techniques are investigated. The primary geometry of blade uses a standard NACA-65 series airfoil, which has been tolerated by 50% variation in circular leading edge radius. Mesh requirements of flow simulation for intended purposes are studied in detail and some recommendations are proposed to be implemented in numerical aeroelastic simulations. Accuracy and fidelity of LES results are studied with extraction of power spectra around the blade and the portion of resolved energy is also estimated. Results suggest that the order of accuracy and grid density highly affect the small-scale flow phenomena. The variations in leading edge radius also have great effect on energy distribution among resolved scales.
Keywords
Aeroelasticity
Large Eddy Simulation
Turbulent
Stall
Axial Compressor
[1] P. G. Tucker, Computation of unsteady turbomachinery flows: Part 1-Progress and challenges, Progress in Aerospace Sciences, Vol. 47, No. 7, pp. 522–545, 2011.
[2] S. L. F. Holzinger, Self-Excited blade vibration experimentally investigated in transonic compressor - acoustic responce, Journal of Turbomachinery, Vol.138, No.4, pp. 1–12, 2016.
[3] P. G. Tucker, Computation of unsteady turbomachinery flows: Part 2-LES and hybrids, Progress in Aerospace Sciences, Vol. 47, No. 7, pp. 546–569, 2011.
[4] S. B. Pope, Turbulent Flows, pp. 558-641, NewYork: Cambridge University Press, 2001.
[5] M. Inoue, M. Kuroumaru, M. Furukawa, Behavior of tip leakage flow behind an axial compressor rotor, Engineering for Gas Turbine and Power, Vol. 108, pp. 7–14, 1986.
[6] R. Taghavi-Zenouz, S. Abbasi, Alleviation of spike stall in axial compressors utilizing grooved casing treatment, Chinese Journal of Aeronautics, Vol. 28, No. 3, pp. 649–658, 2015.
[7] R. T. Zenouz, M. Hosein, A. Behbahani, A. Khoshnejad, Experimental investigation of air injection effects on rotating stall alleviation in an axial compressor, Modares Mechanical Engineering, Vol. 16, No. 7, pp. 267–274, 2016. (in Persian فارسی(
[8] R. Taghavi-Zenouz, M. H. Ababaf-Behbahani, Improvement of aerodynamic performance of a low speed axial compressor rotor blade row through air injection, Aerospace Science and Technology, Vol. 72, pp. 409–417, 2017.
[9] N. Akbari, Numerical simulation of active control of instabilities in an axial compressor under distorted inlet flow, Modares Mechanical Engineering, Vol. 17, No. 1, pp. 193–202, 2017. (in Persian فارسی(
[10] H. Im, X-Y Chen,G. Zha, Detached-eddy simulation of rotating stall inception for a full-annulus transonic rotor, J. Propuls. Power, Vol. 28, No. 4, pp. 782–798, 2012.
[11] M. Jalalifar, B. G. Dehkordi, S. Fallah, Numerical study of mid-span damper effect on the pattern of flow and operation of transonic compressor blades, Modares Mechanical Engineering, Vol. 16, No. 10, pp. 218–228, 2016. (in (فارسی Persian
[12] S. Fallah, B. Ghadiri, G. Heidarinejad, Numerical study of aeroelastic instability behavior of Nasa 37 transonic compressor rotor blades, Modares Mechanical Engineering, Vol. 17, No. 3, pp. 123–134, 2017. (in Persian فارسی )
[13] S. Fallah, B. G. Dehkordi, G. Heidarinejad, Numerical investigation of turbulence characteristics of flow in fixed and oscillating transonic fan cascade, Modares Mechanical Engineering, Vol. 14, No. 16, pp. 231–242, 2015. (in Persian فارسی(
[14] I. H. Abbott, A. E. Von Doenhoff, Theory of Wing Sections: Including a Summary of Airfoil data, pp. 46–80, New York: Dover Publications INC., 1959.
[15] R. Taghavi-Zenouz and S. Abbasi, Multiple spike stall cells in low speed axial compressor rotor blade row, Journal of Theoretical and Applied Mechanics, Vol. 53, No. 1, pp. 47–57, 2015.
[16] ANSYS, ANSYS CFX-Solver Theory Guide, Vol. 15317, No. April, pp. 724– 746, 2009.
[17] J. C. Tyacke, P. G. Tucker, Future use of large eddy simulation in aero‐engines, Journal of Turbomachinery, Vol. 137, No. 8, pp. 1–16, 2015.
[18] E. Garnier, N. Adams, P. Sagaut, Large Eddy Simulation for Compressible Flow, Springer, 2003.
[19] W. W. Kim, S. Menon, Application of the localized dynamic subgrid-scale model to turbulent wall-bounded flows, 35th Aerospace Sciences Meeting and Exhibit, January 1997.
[20] C. Hirsch, Numerical Computation of Internal and External Flows, Second Edittion, Butterworth-Heinemann: Wiley, 2007.
[21] G. Saddoughi, V.Veeravalli, Local isotropy in turbulent boundary layers at high Reynolds number, Journal of Fluid Mechanics, Vol. 268, pp. 333–372, 1994.
[22] D. Sundararajan, The discrete Fourier Transform : Theory, Algorithms and Applications, pp. 31–60, World Scientific, 2001.
[23] F. M. Denaro, What does finite volume-based implicit filtering really resolve in large-eddy simulations?, Journal of Computational Physics , Vol. 230, No. 10, pp. 3849–3883, 2011.
[24] S. B. Pope, Ten questions concerning the large-eddy simulation of turbulent flows, New Journal of Physics, Vol. 6, 2004.
[25] I. B. Celik, Z. N. Cehreli, I. Yavuz, Index of resolution quality for large eddy simulations, Journal of Fluids Engineering, Vol. 127, No. 5, pp. 949–958, 2005.
[26] M. Klein, J. Meyers, B. Geurts, Assessment of LES quality measures using the error landscape approach, Quality and Reliability of Large-Eddy Simulations, Vol. 56, pp. 131–142, 2008.
[27] B. P. Leonard, The ultimate conservative difference scheme applied to unsteady one-dimensional advection, Computer Methods in Applied Mechanics and Engineering, Vol. 88, No. 1, pp. 17–74, 1991.
[28] J. Fröhlich, W. Rodi ,Introduction to Large Eddy Simulation of Turbulent Flow,Karlsruhe, pp. 1-31, 2002.
[29] ANSYS, ANSYS CFX-Pre User’s Guide, Vol. 15317, No. November, pp. 310–360, 2013.
[30] J. Meyers, B. Geurts, P. Sagaut, Quality and reliability of Large Eddy Simulation, Springer, 2008.
[31] A. Keating, U. Piomelli, E. Balaras, H. J. Kaltenbach, A priori and a posteriori tests of inflow conditions for large-eddy simulation, Physics of fluids, Vol. 16, No. 12, pp. 4696–4712, 2004.
[32] P. Sagaut, E. Garnier, E. Tromeur, L. Larchevêque, E. Labourasse, turbulent inflow conditions for large-eddy-simulation of compressible wall-bounded flows, AIAA Journal, Vol. 42, No. 3, pp. 469–477, 2004.
[33] E. Asgari, M. Tadjfar, Assessment of four inflow conditions on large-eddy simulation of a gently curved backward-facing step, Journal of Turbulence, Vol. 18, No. 1, pp. 61–86, 2017.
[34] J. D. Denton, Some limitations of turbomachinery CFD, ceedings ASME Turbo Expo, pp. 1–11, 2010.
[35] N. Gourdain, Prediction of the unsteady turbulent flow in an axial compressor stage, Part 1: Comparison of unsteady RANS and LES with experiments, Computers and Fluids, Vol. 106, pp. 119–129, 2015.
[36] N. Gourdain, Prediction of the unsteady turbulent flow in an axial compressor stage, Part 2: Analysis of unsteady RANS and LES data, Computers and Fluids, Vol. 106, pp. 67–78, 2015.
[37] D. Degani, A. Seginer, Y. Levy, Graphical visualization of vortical flows by means of helicity, AIAA Journal, Vol. 28, No. 8, pp. 1347–1352, 1990.
Modares Mechanical Engineering
Volume 18, Issue 3
May 2018
Pages 153-163