Influence of taper, Reynolds number and Mach number on the secondary flow field of a highly loaded turbine cascade

Duden, Arno; Fottner, Leonhard

doi:10.1177/095765099721100401

Cited by 22 publications

(28 citation statements)

References 5 publications

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“…The cascade with a rearloaded pressure distribution was observed to result in smaller secondary losses than the frontloaded cascade. As well, it is known from investigations regarding the influence of incidence (e. g. Hodson and Dominy, 1986) and from the authors previous studies concerning the effect of endwall taper (Duden and Fottner, 1997) that an increased loading, especially in the front part of the cascade, strongly increases the secondary flow.…”

Section: Introductionmentioning

confidence: 79%

Controlling the Secondary Flow in a Turbine Cascade by 3D Airfoil Design and Endwall Contouring

Duden

Raab

Fottner

1998

Volume 1: Turbomachinery

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A highly loaded turbine cascade has been redesigned with the objective to reduce the secondary flow by applying endwall contouring and 3D airfoil design in the endwall regions. The overall loading and the axial area ratio of the cascade have been kept constant. With the tools of a 3D design environment a systematic study has been carried out regarding several features of the endwall pressure distribution and their influence on the secondary flow. Two optimized configurations have been investigated in a high speed cascade wind tunnel. The flow field traverses showed improvements concerning the radial extent of the secondary flow and a decrease in secondary loss of 26 per cent. Unfortunately this reduction was counterbalanced by increased profile losses and higher inlet losses due to increased blockage. The striking feature of the cascade with endwall contouring and 3D airfoil design was a significant reduction of the exit flow angle deviations connected with the secondary flow. The predictions obtained by the 3D Navier-Stokes solver TRACE_S showed a remarkable agreement with the experimental results.

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Section: Introductionmentioning

confidence: 79%

Controlling the Secondary Flow in a Turbine Cascade by 3D Airfoil Design and Endwall Contouring

Duden

Raab

Fottner

1998

Volume 1: Turbomachinery

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“…Increasing the outlet Mach number results in smaller Zweifel coefficients, higher row velocity ratios and higher Reynolds numbers, as presented in more aft-loaded midspan loading distributions, as shown in Figure 7.11, and slightly smaller profile losses (Chapter 6). These results regarding the effects of Mach number on loading distributions are consistent with the findings by Camus et al (1984), Duden and Fottner (1997) and Dossena et al (1997). Figure 7.12, on the other hand, show evidence of suction side separation (S 5 ) on both airfoils.…”

Section: Midspan Blade Loading Distributionssupporting

confidence: 92%

“…Similar trends appear in the near-wall region for SL1F, albeit less pronounced due to a weaker corner vortex. These results are consistent with the findings of Duden and Fottner (1997). Figure 7.17(b) shows significantly higher secondary kinetic energy production for the same downstream location for SL2F than for SL1F at all three Mach numbers.…”

Section: Pitchwise Mass-averagedsupporting

confidence: 90%

“…Due to potential probe interference effects, such as flow blockage inside the passage, the majority of the measurements have been obtained only upstream and downstream of the cascades. Flow visualization techniques, such as surface oil film visualization (Camus et al 1984;Duden and Fottner, 1997), and nonintrusive measurement techniques, such as laser Doppler anemometry and Schlieren photography (Michelassi et al, 1998), have been utilized to investigate the flow field structures inside the blade passage. Additionally, CFD has been used to provide complementary data, which may not be easily obtained from the experiments.…”

Section: Flow Compressibilitymentioning

confidence: 99%

“…to 110% axial chord downstream of the trailing edge, was eight times higher than SKE dissipation at an outlet Mach number of 1.02. Duden and Fottner (1997) also investigated the effects of flow compressibility and Reynolds number variation on secondary flows for two highly loaded turbine cascades.…”

Section: Flow Compressibilitymentioning

confidence: 99%

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Endwall Flows in Transonic Turbine Cascades

Taremi¹

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The results of an investigation of the midspan and endwall flows in transonic linear turbine cascades are documented here. A family of five turbine cascades with different levels of flow turning and aerodynamic loading were used for this study to quantify the effects of these parameters on loss generation in compressible flows. Experimental data on these flows are scarce in the open literature. In addition, the application of two different passive flow control techniques for reducing the endwall losses is examined here: these are referred to as endwall contouring, and airfoil pressure-side modification. The experimental investigations were conducted in the Pratt and Whitney Canada (PWC) High-Speed Wind Tunnel Laboratory at Carleton University. The measurements were made using a seven-hole pressure probe downstream of the cascades at both design and off-design Mach numbers. In addition to the measurements, surface flow visualization was conducted to assist in the interpretation of the flow physics. The results from complementary numerical investigations are also presented, and compared with the experimental data. Overall, the examined secondary flow structures are in agreement with previous lowspeed findings. However, in contrast to low-speed results, the downstream mixing losses are mainly attributed to the dissipation of primary kinetic energy in the present study. Raising the exit Mach number results in weaker secondary flow structures and smaller secondary losses.The experimental results demonstrate that endwall contouring is a viable option for mitigating the secondary flows, particularly for the more highly-loaded cascade. The modification of the airfoil pressure surface is also found to provide a significant benefit in terms of endwall loss reduction. The differences between the measurements and the computational results highlight the need for detailed experimental investigations.ii Acknowledgments I would like to express my gratitude to my thesis supervisor, Professor Steen Sjolander, for giving me the opportunity to work on this research project. I would also like to thank him for his invaluable advice regarding the interpretation of the results, and for reviewing the text.

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Automated Tactile Sensory Perception of Contact Using the Distributive Approach

Tongpadungrod²,

Brett

Mechatronics and Machine Vision in Practice

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Influence of taper, Reynolds number and Mach number on the secondary flow field of a highly loaded turbine cascade

Cited by 22 publications

References 5 publications

Controlling the Secondary Flow in a Turbine Cascade by 3D Airfoil Design and Endwall Contouring

Controlling the Secondary Flow in a Turbine Cascade by 3D Airfoil Design and Endwall Contouring

Endwall Flows in Transonic Turbine Cascades

Automated Tactile Sensory Perception of Contact Using the Distributive Approach

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