0
Research Papers: Flows in Complex Systems

Benefits of Nonaxisymmetric Endwall Contouring in a Compressor Cascade With a Tip Clearance

[+] Author and Article Information
Mahesh K. Varpe

Department of Aerospace Engineering,
Indian Institute of Technology, Bombay,
Mumbai 400 076, India
e-mail: maheshvarpe@aero.iitb.ac.in

A. M. Pradeep

Department of Aerospace Engineering,
Indian Institute of Technology, Bombay,
Mumbai 400 076, India
e-mail: ampradeep@aero.iitb.ac.in

1Corresponding author.

Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received July 14, 2014; final manuscript received October 23, 2014; published online January 20, 2015. Assoc. Editor: Frank C. Visser.

J. Fluids Eng 137(5), 051101 (May 01, 2015) (15 pages) Paper No: FE-14-1378; doi: 10.1115/1.4028996 History: Received July 14, 2014; Revised October 23, 2014; Online January 20, 2015

This paper describes the design of a nonaxisymmetric hub contouring in a shroudless axial flow compressor cascade operating at near stall condition. Although an optimum tip clearance (TC) reduces the total pressure loss, further reduction in the loss was achieved using hub contouring. The design methodology presented here combines an evolutionary principle with a three-dimensional (3D) computational fluid dynamics (CFD) flow solver to generate different geometric profiles of the hub systematically. The resulting configurations were preprocessed by GAMBIT© and subsequently analyzed computationally using ANSYSFluent©. The total pressure loss coefficient was used as a single objective function to guide the search process for the optimum hub geometry. The resulting three dimensionally complex hub promises considerable benefits discussed in detail in this paper. A reduction of 15.2% and 16.23% in the total pressure loss and secondary kinetic energy (SKE), respectively, is achieved in the wake region. An improvement of 4.53% in the blade loading is observed. Other complimentary benefits are also listed in the paper. The majority of the benefits are obtained away from the hub region. The contoured hub not only alters the pitchwise static pressure gradient but also acts as a vortex generator in an effort to alleviate the total pressure loss. The results confirm that nonaxisymmetric contouring is an effective method for reducing the losses and thereby improving the performance of the cascade.

Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Rose, M. G., 1994, “Non-Axisymmetric Endwall Profiling in the HP NGV's of an Axial Flow Gas Turbine,” ASME Paper No. GT1994-249.
Harvey, N. W., Rose, M. G., Taylor, M. D., Shahpar, S., Hartland, J., and Gregory-Smith, D. G., 2000, “Non-Axisymmetric Turbine End Wall Design: Part I—Three-Dimensional Linear Design System,” ASME J. Turbomach., 122(2), pp. 278–285. [CrossRef]
Hartland, J., Gregory-Smith, D. G., Harvey, N. W., and Rose, M. G., 2000, “Nonaxisymmetric Turbine End Wall Design: Part II—Experimental Validation,” ASME J. Turbomach., 122(2), pp. 286–293. [CrossRef]
Ingram, G., Gregory-Smith, D., and N.Harvey, 2005, “Investigation of a Novel Secondary Flow Feature in a Turbine Cascade With End Wall Profiling,” ASME J. Turbomach, 127(1), pp. 209–214. [CrossRef]
Ingram, G., Gregory-Smith, D., and Harvey, N., 2005, “The Benefits of Turbine Endwall Profiling in a Cascade,” Proc. Inst. Mech. Eng. Part A, 219(1), pp. 49–59. [CrossRef]
Praisner, T. J., Allen-Bradley, E., Grover, E. A., Knezevici, D. C., and Sjolander, S. A., 2007, “Application Of Non-Axisymmetric Endwall Contouring to Conventional and High-Lift Turbine Airfoils,” ASME Paper No. GT2007-27579. [CrossRef]
Germain, T., Nagel, M., Raab, I., Schuepbach, P., Abhari, R. S., and Rose, M., 2008, “Improving Efficiency of a High Work Turbine Using Non-Axisymmetric Endwalls, Part I—Endwall Design and Performance,” ASME Paper No. GT2008-50469. [CrossRef]
Knezevici, D. C., Sjolander, S. A., Praisner, T. J., Allen-Bradley, E., and Grover, E. A., 2010, “Measurements of Secondary Losses in a Turbine Cascade With the Implementation of Non-Axisymmetric Endwall Contouring,” ASME J. Turbomach., 132(1), p. 011013. [CrossRef]
LaFleur, R. S., 2008, “Second Vane Total Pressure Loss Due to Endwall Iceform Contouring,” ASME Paper No. GT2008-50439. [CrossRef]
Hu, S., Lu, X., Zhang, H., Zhu, J., and Xu, Q., 2010, “Numerical Investigation of a High-Subsonic Axial-Flow Compressor Rotor With Non-Axisymmetric Hub Endwall,” J. Therm. Sci., 19(1), pp. 14–20. [CrossRef]
Poehler, T., Gier, J., and Jeschke, P., 2010, “Numerical and Experimental Analysis of the Effects of Non-Axisymmetric Contoured Stator Endwalls in an Axial Turbine,” ASME Paper No. GT2010-23350. [CrossRef]
Torre, D., Vázquez, R., de la Rosa Blanco, E., and Hodson, H. P., 2011, “A New Alternative for Reduction in Secondary Flows in Low Pressure Turbines,” ASME J. Turbomach., 133(1), p. 011029. [CrossRef]
Miyoshi, I., Higuchi, S., and Kishibe, T., 2013, “Improving the Performance of a High Pressure Gas Turbine Stage Using a Profiled Endwall,” ASME Paper No. GT2013-95148. [CrossRef]
Snedden, G., Dunn, D., Ingram, G., and Gregory-Smith, D., 2010, “The Performance of a Generic Non-Axisymmetric End Wall in a Single Stage, Rotating Turbine at on and Offdesign Conditions,” ASME Paper No. GT2010-22006. [CrossRef]
Hilfer, M., Ingram, G., and Hogg, S., 2012, “Endwall Profiling With Tip Clearance Flows,” ASME Paper No. GT2012-68488. [CrossRef]
McIntosh, J., MacPherson, R., Ingram, I., and Hogg, S., 2011, “Profiled Endwall Design Using Genetic Algorithms With Different Objective Functions,” ASME Paper No. GT2011-45836. [CrossRef]
Peacock, R. E., 1982, “A Review of Turbomachinery Tip Gap Effects Part 1—Cascades,” Int. J. Heat Fluid Flow, 3(4), pp. 185–193. [CrossRef]
Gbadebo, S. A., Cumpsty, N. A., and Hynes, T. P., 2007, “Interaction of Tip Clearance Flow and Three-Dimensional Separations in Axial Compressors,” ASME J. Turbomach., 129, pp. 679–685. [CrossRef]
Luo, J., Xiong, J., Liu, F., and McBean, I., 2010, “Secondary Flow Reduction by Blade Redesign and Endwall Contouring Using an Adjoint Optimization Method,” ASME Paper No. GT2010-22061. [CrossRef]
Varpe, M. K., and Pradeep, A. M., 2013, “Numerical Investigation of the Effect of Moving Endwall and Tip Clearance on the Losses in a Low Speed Axial Flow Compressor Cascade,” ASME Paper No. GTINDIA2013-3596. [CrossRef]
Varpe, M., and Pradeep, A. M., 2013,“Investigation of the Shear Flow Effect and Tip Clearance on a Low Speed Axial Flow Compressor Cascade,” Int. J. Rotating Mach., 2013, p. 490543. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Planar distribution of control points, marked as “+,” on the hub (endwall) with the wake location

Grahic Jump Location
Fig. 2

Schematic representation of evolutionary algorithm

Grahic Jump Location
Fig. 3

One point crossover between the parent chromosomes

Grahic Jump Location
Fig. 4

Multiblock structured mesh with the O grid around the airfoil and triangular prism mesh in the tip region only

Grahic Jump Location
Fig. 5

Comparison of the static pressure coefficient on the blade surface between experiment and CFD, at midspan and close to the tip

Grahic Jump Location
Fig. 6

Total pressure coefficient along the span in the wake region, between experiment and CFD

Grahic Jump Location
Fig. 7

Height contours of the optimum hub

Grahic Jump Location
Fig. 8

Static pressure coefficient on the hub

Grahic Jump Location
Fig. 10

Static pressure coefficient on the blade surface at midspan, close to hub, and tip

Grahic Jump Location
Fig. 11

Contours of static pressure coefficient on blade surface for planar and optimized hub

Grahic Jump Location
Fig. 12

SFL on blade surface

Grahic Jump Location
Fig. 13

Contours of total pressure coefficient in the wake region for axisymmetric and profiled hub

Grahic Jump Location
Fig. 14

Contours of vorticity along the reference flow angle in the wake region

Grahic Jump Location
Fig. 15

Pitchwise mass averaged endwall loss, SKE, and flow deviation along the span, in the wake region

Grahic Jump Location
Fig. 16

Contours of total pressure coefficient on the suction surface side of tip gap, with planar and optimized hub

Grahic Jump Location
Fig. 17

Effect of hub contouring on the flow structure using streamlines

Grahic Jump Location
Fig. 18

Coefficient of total pressure superimposed with secondary flow structure at different axial locations, near the tip in the flow passage

Grahic Jump Location
Fig. 19

Coefficient of total pressure superimposed with secondary streamlines at different axial locations, near the hub in the flow passage

Grahic Jump Location
Fig. 20

Mass averaged total pressure loss coefficient and yaw angle at different axial location

Grahic Jump Location
Fig. 21

Static pressure coefficient in the wake region

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In