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Research Papers

A Three-Zone Modeling Approach for Centrifugal Compressor Slip Factor Prediction

[+] Author and Article Information
Charles Stuart

School of Mechanical and
Aerospace Engineering,
Queen's University Belfast,
Belfast BT9 5AH, UK
e-mail: cstuart05@qub.ac.uk

Stephen Spence

School of Mechanical and
Aerospace Engineering,
Queen's University Belfast,
Belfast BT9 5AH, UK
e-mail: s.w.spence@qub.ac.uk

Dietmar Filsinger

IHI Charging Systems International,
Heidelberg 69126, Germany
e-mail: d.filsinger@ihi-csi.de

Andre Starke

IHI Charging Systems International,
Heidelberg 69126, Germany
e-mail: a.starke@ihi-csi.de

Sung In Kim

School of Mechanical and
Aerospace Engineering,
Queen's University Belfast,
Belfast BT9 5AH, UK
e-mail: s.kim@qub.ac.uk

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received October 11, 2018; final manuscript received December 10, 2018; published online January 16, 2019. Editor: Kenneth Hall.

J. Turbomach 141(3), 031008 (Jan 16, 2019) (12 pages) Paper No: TURBO-18-1288; doi: 10.1115/1.4042248 History: Received October 11, 2018; Revised December 10, 2018

Accurate estimation of slip factor is of paramount importance to ensure centrifugal compressor work input is adequately predicted during the preliminary design process. However, variations in the flow field at impeller exit in both the pitchwise and spanwise directions complicate the evaluation procedure considerably. With the increasing implementation of engine downsizing technologies in the automotive sector, achieving a wide operating range has become a factor of prime importance for centrifugal compressors used in automotive turbocharging applications. As a result of the design features required to achieve this aim, modern impeller geometries have been shown to exhibit an approximately parabolic variation in slip factor across their respective operating maps. By comparison, traditional slip correlations typically exhibit a constant, or at best monotonic, relationship between slip factor and impeller exit flow coefficient. It is this lack of modeling fidelity which the current work seeks to address. In order to tackle these shortcomings, it is proposed that the impeller exit flow should be considered as being made up of three distinct regions: a region of recirculation next to the shroud providing aerodynamic blockage to the stage active flow, and a pitchwise subdivision of the active flow region into jet and wake components. It is illustrated that this hybrid approach in considering both spanwise and pitchwise stratification of the flow permits a better representation of slip factor to be achieved across the operating map. The factors influencing the relative extent of each of these three distinct regions of flow are numerous, requiring detailed investigations to successfully understand their sources and to characterize their extent. A combination of 3D computational fluid dynamics (CFD) data and gas stand test data for six automotive turbocharger compressor stages was employed to achieve this aim. Through application of the extensive interstage static pressure data gathered during gas stand testing at Queen's University Belfast, the results from the 3D CFD models were validated, thus permitting a more in-depth evaluation of the flow field in terms of locations and parameters that could not easily be measured under gas stand test conditions. Building on previous knowledge gained about the variation in shroud side recirculation with geometry and operating condition, the characteristic jet/wake flow structure emanating from the active flow region of the impeller was represented in terms of area and mass flow components. This knowledge allowed individual slip factor values for the jet and wake to be calculated and combined to give an accurate passage average value which exhibited the distinctive nonlinear variation in slip across the operating map which is frequently absent from existing modeling methods. Fundamental considerations of the flow phenomena in each region provided explanation of the results and permitted a modeling approach to be derived to replicate the trends observed in both the experimental data and the CFD simulations.

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References

Harley, P. , Spence, S. W. , Filsinger, D. , Dietrich, M. , and Early, J. , 2014, “ Meanline Modeling of Inlet Recirculation in Automotive Turbocharger Centrifugal Compressors,” ASME J. Turbomach., 137(1), p. 011007. [CrossRef]
Stuart, C. , Spence, S. W. , Filsinger, D. , Starke, A. , and Kim, S. I. , 2018, “ Characterizing the Influence of Impeller Exit Recirculation on Centrifugal Compressor Work Input,” ASME J. Turbomach., 140(1), p. 011005.
Japikse, D. , 1985, “ Assessment of Single and Two-Zone Modelling of Centrifugal Compressors, Studies in Component Performance—Part 3,” ASME Paper No. 85-GT-73.
Eckardt, D. , 1978, “ Investigation of the Jet-Wake Flow of a Highly Loaded Centrifugal Compressor Impeller,” National Aeronautics and Space Administration, Washington, DC, Report No. NASA-TM-75232. https://ntrs.nasa.gov/search.jsp?R=19780008108
Whitfield, A. , 1974, “ Slip Factor of a Centrifugal Compressor and Its Variation With Flow Rate,” Proc. Inst. Mech. Eng., 188(1), pp. 415–423. pp [CrossRef]
Dean, R. C. , Wright, D. , and Runstadler, P. W. , 1970, “ Fluid Mechanics Analysis of High-Pressure-Ratio Centrifugal Compressor Data,” U.S. Army Aviation Materiel Laboratories, Fort Eustis, VA, Report No. 69-76. http://www.academia.edu/4040320/USAAVLABS_TECHNICAL_REPORT_65-79_AN_INVESTIGATION_OF_END_PLATES_TO_REDUCE_THE_DRAG_OF_PLANAR_WINGSAN_INVESTIGATION_OF_END_PLATES_TO_REDUCE_THE_DRAG_OF_PLANAR_WINGSCONTENTS
Qiu, X. , Japikse, D. , Zhao, J. , and Anderson, M. R. , 2011, “ Analysis and Validation of a Unified Slip Factor Model for Impellers at Design and Off-Design Conditions,” ASME J. Turbomach., 133(4), p. 041018. [CrossRef]
Weisner, F. J. , 1967, “ A Review of Slip Factors for Centrifugal Impellers,” ASME J. Eng. Power, 89, pp. 558–572. [CrossRef]
Stodola, A. , 1945, Steam and Gas Turbines, McGraw-Hill, New-York.
Moore, J. , Moore, J. G. , and Johnson, M. W. , 1977, “ On Three-Dimensional Flow in Centrifugal Impellers,” Aeronautical Research Council, London, Paper No. 1384.
Stern, F. , Wilson, R. V. , Coleman, E. W. , and Paterson, E. G. , 2001, “ Comprehensive Approach to Verification and Validation of CFD Simulations—Part 1: Methodology and Procedures,” ASME J. Fluids Eng., 123(4), pp. 793–802. [CrossRef]
Lüdtke, K. H. , 2004, Process Centrifugal Compressors: Basics, Function, Operation, Design, Application, Springer-Verlag, Berlin.
Weber, C. R. , and Koronowski, M. E. , 1986, “ Meanline Performance Prediction of Volutes in Centrifugal Compressors,” ASME Paper No. 86-GT-216.
Hong, S. S. , and Kang, S. H. , 2002, “ Exit Flow Measurements of a Centrifugal Pump Impeller,” KSME Int. J., 16(9), pp. 1147–1155. [CrossRef]
Sirakov, B. , and Casey, M. , 2011, “ Evaluation of Heat Transfer Effects on Turbocharger Performance,” ASME Paper No. GT2011-45887.
Hildebrandt, A. , and Genrup, M. , 2007, “ Numerical Investigation of the Effect of Different Back Sweep Angle and Exducer Width on the Impeller Outlet Flow Pattern of a Centrifugal Compressor With Vaneless Diffuser,” ASME J. Turbomach., 129(4), pp. 429–433.

Figures

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Fig. 1

Schematic detailing constituents of impeller exit flow

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Fig. 2

Jet and wake velocity triangles for C-6 at low-mass flow operating condition (mass flow averaged values)

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Fig. 3

Diagram illustrating the presence of wake flow on the suction side of blades

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Fig. 4

Diagram representing impeller exit throat relative eddy (accounting for the presence of wake flow)

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Fig. 5

Comparison of CFD extracted impeller exit blockage with that predicted by Eq. (3) [2]

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Fig. 6

Single-passage CFD setup

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Fig. 7

Postprocessing procedure for jet and wake slip factor evaluation

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Fig. 8

Extracted wake mass flow fraction for all six compressor geometries

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Fig. 9

Comparison between disk friction and recirculation parasitic loss coefficients and stage work coefficient for C-3

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Fig. 10

Comparison between slip factors from CFD and test data for C-3

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Fig. 11

Comparison of Qiu and proposed slip factor modeling approaches with CFD data for C-1

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Fig. 12

Comparison of Qiu and proposed slip factor modeling approaches with CFD data for C-2

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Fig. 13

Comparison of Qiu and proposed slip factor modeling approaches with CFD data for C-3

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Fig. 14

Comparison of Qiu and proposed slip factor modeling approaches with CFD data for C-4

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Fig. 15

Comparison of Qiu and proposed slip factor modeling approaches with CFD data for C-5

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Fig. 16

Comparison of Qiu and proposed slip factor modeling approaches with CFD data for C-6

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Fig. 17

Comparison of F-factor values from Qiu and three-zone modeling approaches for C-3

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Fig. 18

Comparison of total pressure ratio prediction for C-6 with Qiu and three-zone slip factor models

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