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Research Papers

Radial Turbine Rotor Response to Pulsating Inlet Flows

[+] Author and Article Information
Teng Cao

e-mail: tc367@cam.ac.uk

Liping Xu

Whittle Laboratory,
Department of Engineering,
University of Cambridge,
Cambridge CB3 0DY, UK

Ricardo F. Martinez-Botas

Dept. of Mechanical Engineering,
Imperial College London,
London SW72AZ, UK

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received July 30, 2013; final manuscript received August 6, 2013; published online December 27, 2013. Editor: Ronald Bunker.

J. Turbomach 136(7), 071003 (Dec 27, 2013) (10 pages) Paper No: TURBO-13-1174; doi: 10.1115/1.4025948 History: Received July 30, 2013; Revised August 06, 2013

The performance of automotive turbocharger turbines has long been realized to be quite different under pulsating flow conditions compared to that under the equivalent steady and quasi-steady conditions on which the conventional design concept is based. However, the mechanisms of this phenomenon are still intensively investigated nowadays. This paper presents an investigation of the response of a stand-alone rotor to inlet pulsating flow conditions by using a validated unsteady Reynolds-averaged Navier–Stokes solver (URANS). The effects of the frequency, the amplitude, and the temporal gradient of pulse waves on the instantaneous and cycle integrated performance of a radial turbine rotor in isolation were studied, decoupled from the upstream turbine volute. A numerical method was used to help gain the physical understanding of these effects. A validation of the numerical method against the experiments on a full configuration of the turbine was performed prior to the numerical tool being used in the investigation. The rotor was then taken out to be studied in isolation. The results show that the turbine rotor alone can be treated as a quasi-steady device only in terms of cycle integrated performance; however, instantaneously, the rotor behaves unsteadily, which increasingly deviates from the quasi-steady performance as the local reduced frequency of the pulsating wave is increased. This deviation is dominated by the effect of quasi-steady time lag; at higher local reduced frequency, the transient effects also become significant. Based on this study, an interpretation and a model of estimating the quasi-steady time lag have been proposed; a criterion for unsteadiness based on the temporal local reduced frequency concept is developed, which reduces to the Λ criterion proposed in the published literature when cycle averaged. This in turn emphasizes the importance of the pressure wave gradient in time.

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References

Palfreyman, D., and Martinez-Botas, R. F., 2005, “The Pulsating Flow Field in a Mixed Flow Turbocharger Turbine: An Experimental and Computational Study,” ASME J. Turbomach., 127(1), pp. 144–155. [CrossRef]
Wallace, F., and Blair, G., 1965, “The Pulsating Flow Performance of Inward Radial Flow Turbines,” ASME Paper No. 65-GTP-21.
Benson, R., and Scrimshaw, K., 1965, “An Experimental Investigation of Non-Steady Flow in a Radial Gas Turbine,” Proc. I. Mech. E., 180(10), pp. 74–85. [CrossRef]
Kosuge, H., Yamanaka, N., Ariga, I., and Watanabe, I., 1976, “Performance of Radial Flow Turbines Under Pulsating Flow Conditions,” ASME J. Eng. Power, 98(1), pp. 53–59. [CrossRef]
Capobianco, M., Gambarotta, A., and Cipolla, G., 1989, “Influence of the Pulsating Flow Operation on the Turbine Characteristics of a Small Internal Combustion Engine Turbocharger,” Proc. of IMechE, Paper No. C372/019.
Capobianco, M., and Gambarotta, A., 1990, “Unsteady Flow Performance of Turbocharger Radial Turbines,” Proc. of IMechE, Paper No. C405/017.
Dale, A., and Watson, N., 1986, “Vaneless Radial Turbocharger Turbine Performance,” IMechE Turbocharging and Turbochargers, Paper No. C110/86.
Yeo, J., and Baines, N., 1990, “Pulsating Flow Behavior in a Twin-Entry Vaneless Radial Inflow Turbine,” IMechE Turbocharging and Turbochargers, Paper C405/004, pp 113–122.
Winterbone, D., Nikpour, B., and Alexander, G., 1990, “Measurement of the Performance of a Radial Inflow Turbine in Conditional Steady and Unsteady Flow,” Proceedings of the 4th International Conference on Turbocharging and Turbochargers, London, May 22–24.
Abidat, M., Hachemi, M., Hamidou, M., and Baines, N., 1998, “Prediction of the Steady and Non-Steady Flow Performance of a Highly Loaded Mixed Flow Turbine,” IMechE A J. Power Energy, 212(3), pp. 173–184. [CrossRef]
Karamanis, N., Martinez-Botas, R. F., and Su, C. C., 2001, “Mixed Flow Turbines: Inlet and Exit Flow Under Steady and Pulsating Conditions,” ASME J. Turbomach., 123(2), pp. 359–371. [CrossRef]
Szymko, S., Martinez-Botas, R. F., and Pullen, K. R., 2005, “Experimental Evaluation of Turbocharger Turbine Performance Under Pulsating Flow Conditions,” ASME Paper No. GT2005-68878. [CrossRef]
Rajoo, S., and Martinez-Botas, R. F., 2010, “Unsteady Effect in a Nozzled Turbocharger Turbine,” ASME J. Turbomach., 132(3), p. 031001. [CrossRef]
Copeland, C., Martinez-Botas, R., and Seiler, M., 2012, “Unsteady Performance of a Double Entry Turbocharger Turbine With a Comparison to Steady Flow Conditions,” ASME J. Turbomach., 134(2), p. 021022. [CrossRef]
Baines, N., Hajilouy-Benisi, A., and Yeo, J., 1994, “The Pulse Flow Performance and Modelling of Radial Inflow Turbines,” IMechE International Conference on Turbocharging and Turbochargers, London, June 7–9, Paper No. C484/006/94, pp. 209–220.
Chen, H., Hakeem, I., and Martinez-BotasR.F., 1996, “Modelling of a Turbocharger Turbine Under Pulsating Inlet Conditions,” IMechE A J. Power Energy, 210(51), pp. 397–408. [CrossRef]
Costall, A., Szymko, S., Martinez-Botas, R. F., Filsinger, D., and NinkovicD., 2006, “Assessment of Unsteady Behavior in Turbocharger Turbines,” ASME Paper No. GT2006-90348. [CrossRef]
Lam, J., Roberts, Q., and McDonnell, G., 2002, “Flow Modelling of a Turbocharger Turbine Under Pulsating Flow,” 7th International Conference on Turbochargers and Turbocharging, London, May 14–15, pp. 181–196.
Padzillah, M. H., Rajoo, S., and Martinez-Botas, R. F., 2012, “Numerical Assessment of Unsteady Flow Effects on a Nozzled Turbocharger Turbine,” ASME Paper No. GT2012-69062. [CrossRef]
Hellstrom, F., and Fuchs, L., 2009, “Numerical Computational of the Pulsatile Flow in a Turbocharger With Realistic Inflow Conditions From an Exhaust Manifold,” ASME Paper No. GT2009-59619. [CrossRef]
Chen, H., and Winterbone, D., 1990, “A Method to Predict Performance of Vaneless Radial Turbines Under Steady and Unsteady Flow Conditions,” IMechE Turbocharging and Turbochargers, Paper No. C405/008, pp 13–22.
Benson, R., 1974, “Nonsteady Flow in a Turbocharger Nozzleless Radial Gas Turbine,” SAE Technical Paper 740739. [CrossRef]
Baines, N. C., 2010, “Turbocharger Turbine Pulse Flow Performance and Modelling 25 Years On,” IMechE 9th International Conference on Turbochargers and Turbocharging, London, May 19–20, Paper No. C1302/028.
Winterbone, D., Nikpour, B., and Frost, H., 1991, “A Contribution to the Understanding of Turbocharger Turbine Performance in Pulsating Flow,” Proc. Inst. Mech. Eng., Part C: Mech. Eng. Sci., Paper No. C433/011. pp. 19–28.
Copeland, C., Newton, P., Martinez-Botas, R. F., and Seiler, M., 2012, “A Comparison of Timescales Within a Pulsed Flow Turbocharger Turbine,” IMechE 10th International Turbochargers and Turbocharging, London, May 15–16.
Costall, A., and Martinez-Botas, R. F., 2007, “Fundamental Characterization of Turbocharger Turbine Unsteady Flow Behavior,” ASME Paper No. GT2007–28317. [CrossRef]
Denton, J. D., 1992, “The Calculations of Three Dimensional Viscous Flow Through Multistage Turbomachines,” ASME J. Turbomach., 144, pp. 18–26. [CrossRef]
Denton, J. D., 2002, “The Effects of Lean and Sweep on Transonic Fan Performance: A Computational Study,” Task Quarterly, 6(1), pp. 7–23.

Figures

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Fig. 1

Computational model of the turbine: (a) the transition duct, the turbine volute, and the exit pipe; (b) the turbine rotor; (c) the back clearance of the turbine rotor

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Fig. 2

Steady state turbine performance: (a) inlet mass flow function versus pressure ratio; (b) efficiency versus velocity ratio

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Fig. 3

Turbine performances under pulsating flow conditions comparing with quasi-steady data: (a) inlet mass flow function versus pressure ratio; (b) power output versus pressure ratio

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Fig. 4

Circumferential averaged flow angle at the inlet of the turbine rotor

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Fig. 5

Designed pulse wave forms with different frequencies

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Fig. 6

Turbine rotor responses to different inlet pulse frequencies: (a) inlet mass flow function versus pressure ratio, (b) power output versus pressure ratio

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Fig. 7

Phase shifted turbine power output against pressure ratio

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Fig. 8

Turbine rotor cycle integrated performances under different inlet pulse frequency conditions

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Fig. 9

Designed pulse wave forms with different amplitudes

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Fig. 10

Turbine rotor responses to different inlet pulse amplitudes: (a) inlet mass flow function versus pressure ratio, (b) power output versus pressure ratio

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Fig. 11

Phase shifted turbine power output versus pressure ratio

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Fig. 12

Turbine rotor cycle integrated performances under different inlet pulse amplitude conditions

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Fig. 13

Designed pulse wave forms with different wave front gradients

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Fig. 14

Turbine rotor responses to different inlet pulse wave front gradients: (a) inlet mass flow function versus pressure ratio, (b) power output versus pressure ratio

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Fig. 15

Phase shifted turbine power output versus pressure ratio

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Fig. 16

Turbine rotor cycle integrated performances under different inlet pulse wave front gradient conditions

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Fig. 17

Sketch to show temporal local concept

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