Purge flow effects on rotor hub endwall heat transfer with extended endwall contouring into the disk cavity

Hänni, Dominic D.; Schädler, Rainer; Abhari, Reza S.; Kalfas, Anestis I.; Schmid, Gregor; Lutum, Ewald; Lecoq, N.

doi:10.33737/jgpps/109838

Cited by 7 publications

(3 citation statements)

References 25 publications

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“…A similar profile optimization on five radial sections has been conducted to generate this airfoil. In order to compensate for additional secondary flow losses, the airfoil has been equipped with a more advanced EWC as described in (Hänni et al, 2019). The optimization target was the 1.5-stage efficiency.…”

Section: Rotor Designs: Numerical Optimization and Geometrical Detailsmentioning

confidence: 99%

Noise characteristics of a reduced blade count rotor with improved stage efficiency

Schädler

Hänni

Kalfas

et al. 2019

J. Glob. Power Propuls. Soc.

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A reduction in rotor blade count in combination with a gain in aerodynamic performance is a desirable design goal for gas turbines to reduce the overall operational costs. Reducing the number of blades provokes inherently an increase in blade loading which drives the secondary flow strength. In the presented experimental work, the results of inter-stage probe measurements in a highly loaded 1.5-stage axial turbine rig show the potential to improve the stage efficiency for a reduced blade count rotor with respect to a baseline configuration with more blades. Time-resolved probe measurements reveal the detrimental effects on the turbine tonal noise level. It is found that the periodic vorticity fluctuations induced by the interaction of the rotor passage secondary flow structures with the potential field of the downstream stator, leads at specific span positions to a strong increase in the noise level at rotor exit with respect to the baseline. Both, the downstream effect of the convected rotor flow structures as well as the periodic interaction of the second stator originated flow structures are found to drive the acoustic field of the turbine. Overall, the stage efficiency benefit achievement of 0.4% for a 22% reduction in rotor blade count is derogated by an increase in tonal noise by up to 13 dB at the second stator exit.

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Section: Rotor Designs: Numerical Optimization and Geometrical Detailsmentioning

confidence: 99%

Noise characteristics of a reduced blade count rotor with improved stage efficiency

Schädler

Hänni

Kalfas

et al. 2019

J. Glob. Power Propuls. Soc.

Self Cite

View full text Add to dashboard Cite

show abstract

“…A similar profile optimization on five radial sections has been conducted to generate this airfoil. In order to compensate for additional secondary flow losses, this airfoil has been equipped with a more advanced EWC as described in (Hänni et al, 2019). The optimization target was the 1.5- stage efficiency.…”

Section: Turbine Operating Conditionsmentioning

confidence: 99%

Noise Characteristics of a Reduced Blade Count Rotor with Improved Stage Efficiency

Schädler¹,

Hänni²,

Kalfas³

et al. 2019

GPPS Zurich19

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A reduction in rotor blade count in combination with a gain in aerodynamic performance is a desirable design goal for gas turbines to reduce the overall operational costs. Reducing the number of blades provokes inherently an increase in blade loading which drives the secondary flow strength. In the presented experimental work, the results of inter-stage probe measurements in a highly loaded 1.5stage axial turbine rig show the potential to improve the stage efficiency for a reduced blade count rotor with respect to a baseline configuration with more blades. Time-resolved probe measurements reveal the detrimental effects on the turbine tonal noise level. It is found that the periodic vorticity fluctuations induced by the interaction of the rotor passage secondary flow structures with the potential field of the downstream stator, leads at specific span positions to a strong increase in the noise level at rotor exit with respect to the baseline. Both, the downstream effect of the convected rotor flow structures as well as the periodic interaction of the second stator originated flow structures are found to drive the acoustic field of the turbine. Overall, the stage efficiency benefit achievement of 0.4% for a 22% reduction in rotor blade count is derogated by an increase in tonal noise by up to 13 dB at the second stator exit.

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“…An infrared based measurement technique was used to perform heat transfer measurements on the rotor blade tip. The publications from (Lazzi Gazzini et al, 2017b), (Lazzi Gazzini et al, 2017a) and (Hänni et al, 2019) provide a detailed description of the setup, which was adopted for the blade tip measurements and is only briefly outlined here.…”

Section: Heat Transfer Measurement Setupmentioning

confidence: 99%

Variable Blade Tip Geometry Inserts for Combined Aerothermal Measurements for Bladed Disk Rotors

Hänni¹,

Schädler²,

Kalfas³

et al. 2019

Proceedings of Global Power &Amp; Propulsion Society

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Cost effective experimental testing in turbomachinery requires the integration of multiple geometries in one rotor. So-called rainbow designs, combined with fast response aerodynamic and entropy probes, allow for experimentally investigating different designs in a timely and cost effective manner. The investigation of new blade tip geometries is of particular interest, because tip leakage losses account for approximately one third of the total aerodynamic losses in a turbine stage. This work presents the design, integration, and testing of a variable and exchangeable blade tip setup integrated in a bladed disk rotor. The key features of the concept are high flexibility of the geometry, coupled with the possibility of introducing blade tip coolant flows in bladed disk arrangements, and the integration of tip heat transfer measurements. After successful bench tests, an existing rotor has been modified with three tip inserts of the same geometry, and subsequently tested in the axial turbine research facility LISA at ETH Zurich. A custom-made thin film heater for optical highresolution heat transfer measurements was successfully integrated on the insert and tested during operation. Flow field measurements behind the rotor indicated that the aerodynamics of the rotor is not influenced by installing tip inserts. The setup has proven its robustness in more than 80 days of experimental testing, and has provided some encouraging tip heat transfer data.

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Purge flow effects on rotor hub endwall heat transfer with extended endwall contouring into the disk cavity

Cited by 7 publications

References 25 publications

Noise characteristics of a reduced blade count rotor with improved stage efficiency

Noise characteristics of a reduced blade count rotor with improved stage efficiency

Noise Characteristics of a Reduced Blade Count Rotor with Improved Stage Efficiency

Variable Blade Tip Geometry Inserts for Combined Aerothermal Measurements for Bladed Disk Rotors

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