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RANS simulation of secondary flows in a low pressure turbine cascade: Influence of inlet boundary layer profile

  • Michele, Errante (Department of Mechanical and Aerospace Engineering, Politecnico di Torino) ;
  • Andrea, Ferrero (Department of Mechanical and Aerospace Engineering, Politecnico di Torino) ;
  • Francesco, Larocca (Department of Mechanical and Aerospace Engineering, Politecnico di Torino)
  • 투고 : 2021.12.29
  • 심사 : 2022.09.02
  • 발행 : 2022.09.25

초록

Secondary flows have a huge impact on losses generation in modern low pressure gas turbines (LPTs). At design point, the interaction of the blade profile with the end-wall boundary layer is responsible for up to 40% of total losses. Therefore, predicting accurately the end-wall flow field in a LPT is extremely important in the industrial design phase. Since the inlet boundary layer profile is one of the factors which most affects the evolution of secondary flows, the first main objective of the present work is to investigate the impact of two different inlet conditions on the end-wall flow field of the T106A, a well known LPT cascade. The first condition, labeled in the paper as C1, is represented by uniform conditions at the inlet plane and the second, C2, by a flow characterized by a defined inlet boundary layer profile. The code used for the simulations is based on the Discontinuous Galerkin (DG) formulation and solves the Reynolds-averaged Navier-Stokes (RANS) equations coupled with the Spalart Allmaras turbulence model. Secondly, this work aims at estimating the influence of viscosity and turbulence on the T106A end-wall flow field. In order to do so, RANS results are compared with those obtained from an inviscid simulation with a prescribed inlet total pressure profile, which mimics a boundary layer. A comparison between C1 and C2 results highlights an influence of secondary flows on the flow field up to a significant distance from the end-wall. In particular, the C2 end-wall flow field appears to be characterized by greater over turning and under turning angles and higher total pressure losses. Furthermore, the C2 simulated flow field shows good agreement with experimental and numerical data available in literature. The C2 and inviscid Euler computed flow fields, although globally comparable, present evident differences. The cascade passage simulated with inviscid flow is mainly dominated by a single large and homogeneous vortex structure, less stretched in the spanwise direction and closer to the end-wall than vortical structures computed by compressible flow simulation. It is reasonable, then, asserting that for the chosen test case a great part of the secondary flows details is strongly dependent on viscous phenomena and turbulence.

키워드

과제정보

Computational resources provided by hpc@polito, which is a project of Academic Computing within the Department of Control and Computer Engineering at the Politecnico di Torino (http://www.hpc.polito.it).

참고문헌

  1. Allmaras, S., Johnson, F. and Spalart, P. (2012), "Modifications and clarifications for the implementation of the Spalart-Allmaras turbulence model", Seventh International Conference on Computational Fluid Dynamics (ICCFD7), Big Island, Hawaii, July.
  2. Balay, S., Gropp, W.D., McInnes, L.C. and Smith, B.F. (1997), "Efficient management of parallelism in object-oriented numerical software libraries", Modern Software Tools for Scientific Computing, Birkhauser Boston, Boston, MA, United States.
  3. Cui, J., Rao, V.N. and Tucker, P.G. (2017), "Numerical investigation of secondary flows in a high-lift low pressure turbine", Int. J. Heat Fluid Flow, 63, 149-157. https://doi.org/10.1016/j.ijheatfluidflow.2016.05.018.
  4. de la Blanco, E.R., Hodson, H., Vazquez, R. and Torre, D. (2003), "Influence of the state of the inlet endwall boundary layer on the interaction between pressure surface separation and endwall flows", Proc. Inst. Mech. Eng., Part A: J. Power Energy, 217(4), 433-441. https://doi.org/10.1243/095765003322315496.
  5. Duden, A. and Fottner, L. (1997), "Influence of taper, Reynolds number and Mach number on the secondary flow field of a highly loaded turbine cascade", Proc. Inst. Mech. Eng., Part A: J. Power Energy, 211(4), 309-320. https://doi.org/10.1177/095765099721100401.
  6. Errante, M., Ferrero, A. and Larocca, F. (2022), "Simulation of secondary flows in turbomachinery by the discontinuous Galerkin method", AIP Conf. Proc., 2611, 050005. https://doi.org/10.1063/5.0120392.
  7. Ferrero, A., Larocca, F. and Puppo, G. (2015), "A robust and adaptive recovery-based discontinuous Galerkin method for the numerical solution of convection-diffusion equations", Int. J. Numer Meth. Fluid., 77(2), 63-91. https://doi.org/10.1002/fld.3972.
  8. Garai, A., Diosady, L.T., Murman, S.M. and Madavan, N.K. (2017), "Scale-resolving simulations of bypass transition in a high-pressure turbine cascade using a spectral element discontinuous Galerkin method", J. Turbomach., 104(3), 031004. https://doi.org/10.1115/1.4038403.
  9. Geuzaine, C. and Remacle, J.F. (2009), "Gmsh: A three-dimensional finite element mesh generator with built-in pre- and post-processing facilities", Int. J. Numer. Meth. Eng., 79(11), 1309-1311. https://doi.org/10.1002/nme.2579.
  10. Ghidoni, A., Colombo, A., Rebay, S. and Bassi, F. (2013), "Simulation of the transitional flow in a low pressure gas turbine cascade with a high-order discontinuous Galerkin method", J. Fluid. Eng., 135(7), 071101. https://doi.org/10.1115/1.4024107.
  11. Giuliani, A. (2022), "A two-dimensional stabilized discontinuous galerkin method on curvilinear embedded boundary grids", SIAM J. Scientif. Comput., 44(1), A389-A415. https://doi.org/10.1137/21M1396277.
  12. Goldstein, R. and Spores, R. (1988), "Turbulent transport on the endwall in the region between adjacent turbine blades", J. Heat Transf., 110(4a), 862-869. https://doi.org/10.1115/1.3250586.
  13. Gulizzi, V., Almgren, A.S. and Bell, J.B. (2022), "A coupled discontinuous Galerkin-Finite Volume framework for solving gas dynamics over embedded geometries", J. Comput. Phys., 450, 110861. https://doi.org/10.1016/j.jcp.2021.110861.
  14. Langston, L. (1980), "Crossflows in a turbine cascade passage", J. Eng. Power, 102(4), 866-874. https://doi.org/10.1115/1.3230352.
  15. Langston, L. (2001), "Secondary flows in axial turbines-A review", Ann. NY Acad. Sci., 934(1), 11-26. https://doi.org/10.1111/j.1749-6632.2001.tb05839.x.
  16. Lax, P.D. (1954), "Weak solutions of nonlinear hyperbolic equations and their numerical computation", Commun. Pure Appl. Math., 7, 159-193. https://doi.org/10.1002/cpa.3160070112.
  17. LeVeque, R. (2002), Finite Volume Methods for Hyperbolic Problems, Cambridge University Press, Cambridge, United Kingdom.
  18. Lo, M. and van Leer, B. (2009), "Analysis and implementation of recovery-based discontinuous Galerkin for diffusion", 19th AIAA Computational Fluid Dynamics, San Antonio, Texas, June. https://doi.org/10.2514/6.2009-3786.
  19. Marconcini, M., Pacciani, R., Arnone, A., Michelassi, V., Pichler, R., Zhao, Y. and Sandberg, R. (2019), "Large eddy simulation and RANS analysis of the end-wall flow in a linear low-pressure-turbine cascadepart II: Loss generation", J. Turbomach., 141(5), 051004. https://doi.org/10.1115/1.4042208.
  20. Pandolfi, M. (1984), "A contribution to the numerical prediction of unsteady flows", AIAA J., 22(5), 602- 610. https://doi.org/10.2514/3.48491.
  21. Pichler, R., Zhao, Y., Sandberg, R., Michelassi, V., Pacciani, R., Marconcini, M. and Arnone, A. (2019), "Large-eddy simulation and RANS analysis of the end-wall flow in a linear low-pressure turbine cascade, Part I: Flow and secondary vorticity fields under varying inlet condition", J. Turbomach., 141(12), 121005. https://doi.org/10.1115/1.4045080.
  22. Rusanov, V.V. (1962), "The calculation of the interaction of non-stationary shock waves and obstacles", USSR Comput. Math. Math. Phys., 1(2), 304-320. https://doi.org/10.1016/0041-5553(62)90062-9.
  23. Sieverding, C. (1985), "Recent progress in the understanding of basic aspects of secondary flows in turbine blade passages", J. Eng. Gas Turbin. Power, 107(2), 248-257. https://doi.org/10.1115/1.3239704.
  24. Sieverding, C. and Van Den Bosche, P. (1983), "The use of coloured smoke to visualize secondary flows in a turbine-blade cascade", J. Fluid Mech., 134, 85-89. https://doi.org/10.1017/S0022112083003237.
  25. Wang, H., Olson, S., Goldstein, R. and Eckert, E. (1997), "Flow visualization in a linear turbine cascade of high performance turbine blades", J. Turbomach., 119(1), 1-8. https://doi.org/10.1115/1.2841006.
  26. Yao, M. and He, L. (2012), "Implicit discontinuous Galerkin solution on unstructured mesh for turbine blade secondary flow", J. Turbomach., 142(1), 011004. https://doi.org/10.1115/1.4045551.