×

Effect of periodic wakes and a contoured endwall on secondary flow in a high-lift low-pressure turbine cascade at low Reynolds numbers. (English) Zbl 1496.76011

Summary: The use of a contoured endwall has the potential to suppress endwall secondary flow. Unsteady wakes affect not only the boundary layer characteristics of blade suction surface at blade midspan but also the endwall flow structures. The lack of understanding of the flow mechanism of the combined effects of periodic wakes and contoured endwall on secondary flow limits their roles. This paper presents a experimental and numerical investigation of the endwall secondary flow in a typical high-lift low-pressure turbine cascade. Wakes were produced by moving rods upstream of cascade, and the flow fields at the exit of cascade were measured using a seven-hole pressure probe. The study focused on the combined effect of the upstream wakes and the contoured endwall on the secondary flow as well as the underlying physical mechanisms. The influences of the Reynolds numbers and the contoured endwall on the performance of high-lift low-pressure turbine endwall regions were also discussed. At steady conditions without wakes, the total losses in the turbine cascade increased with decreasing Reynolds number; the most intense passage vortex, counter vortex and corner vortex were observed at a low Reynolds number of 25,000 (based on the axial chord and the inlet velocity). The contoured endwall decreased the cross-passage pressure gradient, and suppressed the passage vortex. Under unsteady conditions, the interaction between upstream wakes and the passage vortex results in reduction of the passage vortex. The combined effect of the contoured endwall and periodic wakes redistributed the endwall pressure and further decreased the cross-passage pressure gradient. Consequently, the intensities of the passage vortex and counter vortex decreased by 17% and 11%, respectively, compared with the flat endwall cascade with wakes. Contoured endwall with wakes reduced secondary kinetic energy of cascade exit by 53.8% than the result of the flat endwall no wake. Which is beneficial to improve the aerodynamic performance of the high-lift low-pressure turbine.

MSC:

76-04 Software, source code, etc. for problems pertaining to fluid mechanics
76U05 General theory of rotating fluids
PDFBibTeX XMLCite
Full Text: DOI

References:

[1] Martinez, Romero; R., Sergio; Gross, Andreas, Numerical investigation of low Reynolds number flow in turbine passage, (55th AIAA aerospace sciences meeting, january. 55th AIAA aerospace sciences meeting, january, Grapevine Texas (2017)), AIAA Paper 2017-1456
[2] Howell, R. J.; Hodson, H. P.; Schulte, V.; Schiffer, H. P.; Haselbach, F.; Harvey, N. W., Boundary layer development in the BR710 and BR715 LP Turbines: the implementation of high lift and ultra high lift concepts, (ASME paper (2001)), GT2001-0441
[3] Sanders, D. D.; Nessler, C. A.; Sondergaard, R.; Polanka, M. D.; Marks, C.; Wolff, M., A CFD and experimental investigation of unsteady wake effects on a highly loaded low pressure turbine blade at low Reynolds number, (ASME paper (2010)), GT2010-22977
[4] Benton, S.; Bons, J. P.; Sondergaard, R., Secondary flow loss reduction through blowing for a high-lift front-loaded low pressure turbine cascade, J Turbomach, 135, 2, Article 021020 pp. (2013)
[5] Zoric, T.; Popovic, I.; Sjolander, S. A.; Praisner, T.; Grover, E., Comparative investigation of three highly loaded LP turbine airfoils: part I — measured profile and secondary losses at design incidence, (ASME paper (2007)), GT2007-27537
[6] Cui, J.; Rao, V. N.; Tucker, P. G., Numerical investigation of secondary flows in a high-lift low pressure turbine, Int J Heat Fluid Flow, 63, 149-157 (2017)
[7] Cui, J.; Tucker, P. G., Numerical study of purge and secondary flows in a low-pressure turbine, J Turbomach, 139, 2, Article 021007 pp. (2016)
[8] Hourmouziadis, J., Aerodynamic design of low pressure turbines, 167 (1989)
[9] Wei, Z. J.; Qiao, W. Y.; Liu, J.; Duan, W. H., Reduction of endwall secondary flow losses with leading-edge fillet in a highly loaded low-pressure turbine, (230 (2016)), 184-195
[10] Brachmanski, R. E.; Niehuis, R.; Bosco, A., Investigation of a separated boundary layer and its influence on secondary flow of a transonic turbine profile, (ASME paper (2014)), GT2014-25890
[11] Hodson, H. P.; Howell, R. J., Bladerow interactions, transion, and high-lift aerofoils in low-pressure turbines, Annu Rev Fluid Mech, 37, 37, 71-98 (2005) · Zbl 1117.76070
[12] Hodson, H.; Dawes, W., On the interpretation of measured profile losses in unsteady wake – turbine blade interaction studies, J Turbomach, 120, 2, 276-284 (1998)
[13] Volino, R. J., Effect of unsteady wakes on boundary layer separation on a very high lift low pressure turbine airfoil, J Turbomach, 134, 1, Article 011011 pp. (2012)
[14] Schneider, C. M.; Schrack, D.; Kuerner, M.; Rose, M. G.; Staudacher, S.; Guendogdu, Y., On the unsteady formation of secondary flow inside a rotating turbine blade passage, (ASME paper (2013)), GT2013-94091
[15] Ciorciari, R.; Kirik, I.; Niehuis, R., Effects of unsteady wakes on the secondary flows in the linear T106 turbine cascade, J Turbomach, 136, 9, Article 091010 pp. (2014)
[16] Satta, F.; Simoni, D.; Ubaldi, M.; Zunino, P.; Bertini, F., Profile and secondary flow losses in a high-lift LPT blade cascade at different Reynolds numbers under steady and unsteady inflow conditions, J Therm Sci, 21, 6, 483-491 (2012)
[17] Lei, Q.; Zhengping, Z.; Huoxing, L.; Wei, L., Upstream wake – secondary flow interactions in the endwall region of high-loaded turbines, Comput Fluids, 39, 9, 1575-1584 (2010) · Zbl 1245.76154
[18] Murawski, C. G.; Vafai, K., Effect of wake disturbance frequency on the secondary flow vortex structure in a turbine blade cascade, J Fluids Eng, 122, 3, 606-613 (2000)
[19] Ingram, G., Endwall profiling for the reduction of secondary flow in turbines (2003), Durham University: Durham University North East England, Ph. D. thesis
[20] Brennan, G.; Harvey, N. W.; Rose, M. G.; Fomison, N.; Taylor, M. D., Improving the efficiency of the trent 500 HP turbine using non-axisymmetric end walls: part 1 — turbine design, (ASME paper (2001)), GT2001-0444
[21] Morris, A. W.H.; Hoare, R. G., Secondary loss measurementsin a cascade of turbine blades with meridional wall profiling, (ASME, winter annual meeting. ASME, winter annual meeting, Houston, Tex (1975))
[22] Rose, M. G., Non-axisymmetric endwall profiling in the HP NGV’s of an axial flow gas turbine, (ASME paper (1994)), GT1994-249
[23] Hartland, J. C.; Gregorysmith, D. G.; Harvey, N. W.; Rose, M. G., Non-axisymmetric turbine end wall design: part II — experimental validation, (ASME paper (1999)), GT1999-338
[24] Dunn, D.; Snedden, G.; Von Backstrom, T., Unsteady effects of a generic non-axisymmetric rotor endwall contour on a 11/2 stage turbine test rig at off design conditions, (ASME paper (2014)), GT2014-25524
[25] Malan, P.; Suluksna, K.; Juntasaro, E., Calibrating the γ-Reθ transition model for commercial CFD, (47th AIAA aerospace sciences meeting. 47th AIAA aerospace sciences meeting, Orlando Florida (2009)), AIAA Paper 2009-1142January 2009
[26] Qu, X.; Zhang, Y.; Lu, X.; Han, G.; Li, Z.; Zhu, J., Effects of periodic wakes on the endwall secondary flow in high-lift low-pressure turbine cascades at low Reynolds numbers, Proc Inst Mech Eng Part G J Aerosp Eng, 0, 0, 1-15 (2017)
[27] Volino, R. J.; Ibrahim, M. B.; Galvin, C. D., Effects of periodic unsteadiness on secondary flows in high pressure turbine passages, (ASME turbo expo 2013: turbine technical conference and exposition (2013)), V06CT42A042
[28] Mahallati, A., Aerodynamics of a low-pressure turbine airfoil under steady and periodically unsteady conditions (2003), Carleton University: Carleton University Ottawa, Canada, Ph. D. thesis
[29] Zorić, Tatjana, Experimental investigation of secondary flows in a family of three highly loaded low-pressure turbine cascades (2006), Carleton University: Carleton University Canada, Ph. D. thesis
[30] Guojun, L.; Xiaoyong, M.; Jun, L., Non-axisymmetric turbine end wall profiling and numerical investigation of its effect on the turbine cascade loss, J Xian Jiaotong Univ, 39, 11, 1169 (2005)
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.