0
Research Papers

Free-Form Versus Ruled Inducer Design in a Transonic Centrifugal Impeller

[+] Author and Article Information
Hamid Hazby

PCA Engineers Ltd.,
Studio 2,
Deepdale Enterprise Park,
Nettleham, Lincoln LN24GB, UK
e-mail: h.hazby@pcaeng.co.uk

Chris Robinson

PCA Engineers Ltd.,
Studio 2,
Deepdale Enterprise Park,
Nettleham, Lincoln LN24GB, UK
e-mail: chris.robinson@pcaeng.co.uk

Michael Casey

PCA Engineers Ltd.,
Biberlinstrasse 20,
Zürich CH-8032, Switzerland
e-mail: michael.casey@casey-s.ch

Daniel Rusch

ABB Turbo Systems Ltd.,
Bruggerstrasse 71 A,
Baden 5401, Switzerland
e-mail: daniel.rusch@ch.abb.com

Rene Hunziker

ABB Turbo Systems Ltd.,
Bruggerstrasse 71 A,
Baden 5401, Switzerland
e-mail: rene.hunziker@ch.abb.com

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received September 21, 2017; final manuscript received September 28, 2017; published online October 31, 2017. Editor: Kenneth Hall.

J. Turbomach 140(1), 011010 (Oct 31, 2017) (12 pages) Paper No: TURBO-17-1173; doi: 10.1115/1.4038176 History: Received September 21, 2017; Revised September 28, 2017

The detailed design of the inducer of a high pressure ratio transonic radial compressor impeller with a design inlet tip relative Mach number of 1.4 is considered. Numerical analysis has been used to compare a datum impeller with ruled inducer design with a number of different free-form design concepts, generated following the same aerodynamic design philosophy. The datum stage and one with a free-form inducer, referred to as “barrelled forward swept,” with forward swept leading edge near the tip and increased chord at midspan, have been manufactured and tested. The tests were performed with the same stationary components, including the casing, vaned diffuser, and the volute. The design with a barrelled forward sweep of the inducer allows the designer more control of the strength and position of the passage shock at the inlet while meeting mechanical constraints. Interestingly, the performance is also enhanced at off-design points at lower tip-speeds. The measurements show that the stage tested with the swept impeller achieves higher efficiency of between 0.5% and 1.6% compared to the datum design, depending on the operating speed. The computational fluid dynamics (CFD) simulations are used to further study the flow at part speeds, in order to explain the causes of the observed performance differences at off design conditions.

Copyright © 2017 by ASME
Your Session has timed out. Please sign back in to continue.

References

Casey, M. V. , 1983, “ A Computational Geometry for the Blades and Internal Flow Channels of Centrifugal Compressors,” ASME J. Eng. Power, 105(2), pp. 288–295. [CrossRef]
Hazby, H. , Casey, M. V. , Numakura, R. , and Tamaki, H. , 2014, “ A Transonic Mixed Flow Compressor for an Extreme Duty,” ASME J. Turbomach., 137(5), p. 051010.
Elfert, M. , Weber, A. , Wittrock, D. , Peters, A. , Voss, C. , and Nicke, E. , 2016, “Experimental and Numerical Verification of an Optimization of a Fast Rotating High Performance Radial Compressor Impeller,” ASME Paper No. GT2016-56546.
ANSYS, 2013, “ANSYS manual, Version 17.1,” ANSYS, Inc., Canonsburg, PA.
Came, P. M. , and Robinson, C. J. , 1998, “ Centrifugal Compressor Design,” Proc. Inst. Mech. Eng., Part C, 213(2), pp. 139–156.
Lohmberg, A. , Casey, M. V. , and Ammann, S. , 2003, “ Transonic Radial Compressor Inlet Design,” Proc. Inst. Mech. Eng., Part A, 217(4), pp. 367–374. [CrossRef]
Freeman, C. , and Cumpsty, N. A. , 1992, “ A Method for the Prediction of Supersonic Compressor Blade Performance,” J. Propul. Power, 8(1), pp. 199–208. [CrossRef]
Calvert, J. , and Ginder, R. B. , 1999, “ Transonic Fan and Compressor Design,” Proc. Inst. Mech. Eng., Part C, 213(5), pp. 419–436. [CrossRef]
Hazby, H. , and Xu, L. , 2009, “ Numerical Investigation of the Effects of the Leading Edge Sweep in a Small Transonic Impeller,” Eigth European Turbomahinery Conference (ETC), Graz, Austria, Mar. 23–27, pp. 459–467. https://www.researchgate.net/publication/289577068_Numerical_investigation_of_the_effects_of_leading_Edge_sweep_in_a_small_transonic_impeller
Denton, J. D. , and Xu, L. , 1998, “ The Exploitation of the Three-Dimensional Flow in Turbomachinery Design,” Proc. Inst. Mech. Eng., Part C, 213(2), pp. 125–137.
Hah, C. , Puterbaugh, S. L. , and Waidia, A. R. , 1998, “Control of Shock Structure and Secondary Flow Field Inside Transonic Compressor Rotors Through Aerodynamic Sweep,” ASME Paper No. 98-GT-561.
Rowlands, P. A. , 2000, “Swept Fan Blade,” Rolls-Royce Plc, Westhampnett, UK, U.S. Patent No. US6071077 A. https://www.google.co.in/patents/US6071077?dq=%E2%80%9CSwept+Fan+Blade,%E2%80%9D&hl=en&sa=X&ved=0ahUKEwjmtrC6sPfWAhUV84MKHVSxBZUQ6AEIJTAA
Hazby, H. , and Xu, L. , 2009, “Role of Tip Leakage in Stall of a Transonic Centrifugal Impeller,” ASME Paper No. GT2009-59372.
Spakovszky, Z. S. , and Roduner, C. H. , 2009, “ Spike and Modal Stall Inception in an Advanced Turbocharger Centrifugal Compressor,” ASME J. Turbomach., 131(3), p. 031012. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Calculation domain and mesh topology

Grahic Jump Location
Fig. 2

Contours of relative Mach number at 90% span of the datum impeller at design mass flow rate

Grahic Jump Location
Fig. 3

Meridional channels of the datum and swept impellers; dashed lines show the position of the leading edges in datum impeller

Grahic Jump Location
Fig. 4

Spanwise distribution of the throat width

Grahic Jump Location
Fig. 5

Contour of relative Mach number (left) and entropy rise (right) at 95% span at the design mass flow

Grahic Jump Location
Fig. 6

Contours of surface static pressure and vectors of relative velocity close to the suction surface the design mass flow rate

Grahic Jump Location
Fig. 10

Position of line generators in the ruled barreled forward swept impeller in the meridional view (left) and in space (right)

Grahic Jump Location
Fig. 9

Spanwise distribution of the throat width

Grahic Jump Location
Fig. 8

Meridional contours of a flank millable impeller with extended chord (left) and a point millable unswept impeller (right); dashed lines show the position of the leading edges in datum impeller

Grahic Jump Location
Fig. 7

CFD predicted in impeller total-to-total pressure ratio and efficiency at the design speed

Grahic Jump Location
Fig. 12

Contours of surface static pressure and vectors of relative velocity close to the suction surface the design mass flow rate

Grahic Jump Location
Fig. 11

Contour of relative Mach number at 95% span at the design mass flow

Grahic Jump Location
Fig. 16

Manufactured datum and barrel type swept impellers

Grahic Jump Location
Fig. 15

Diffuser total pressure loss and static pressure recovery with datum and swept impellers

Grahic Jump Location
Fig. 14

Contours of normalized meridional velocity at the impeller outlet, at the design condition

Grahic Jump Location
Fig. 13

CFD predicted impeller total-to-total pressure ratio and efficiency at the design speed

Grahic Jump Location
Fig. 21

Contours of relative Mach number close to the impeller suction surface at 70% of the design speed at impeller maximum efficiency (right) and near surge (left)

Grahic Jump Location
Fig. 17

Measured stage pressure performance at 100%, 90%, 70%, and 40% of the design speed

Grahic Jump Location
Fig. 18

CFD predicted stage pressure performance at 100%, 90%, 70%, and 40% of the design speed

Grahic Jump Location
Fig. 19

CFD predicted impeller total-to-total efficiency at 100%, 90%, 70%, and 40% of the design speed

Grahic Jump Location
Fig. 20

Contours of relative Mach number at 95% of the span at 90% of the design speed at impeller maximum efficiency (left) and near surge (right)

Grahic Jump Location
Fig. 22

Contours of relative Mach number close to the impeller suction surface at 40% of the design speed at impeller maximum efficiency (right) and near surge (left)

Tables

Errata

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