Axial turbine tip desensitization by injection from a tip trench part 2

Leakage flow sensitivity to injection location

Nikhil M. Rao, Cengiz Camci

Research output: Chapter in Book/Report/Conference proceedingConference contribution

20 Citations (Scopus)

Abstract

In Part 1 of this paper it was shown that discrete jets issuing from a tip platform trench were successful in reducing the total pressure deficit due to tip leakage flow. The specific tip cooling system used in Part 1 had all four injection locations active. This paper examines the effect of the individual location of the injection hole on the tip leakage flow. The investigation was carried out in a large-scale rotating rig. Total pressure downstream of the rotor exit was measured using a Kulite sensor. The measurements were phase-locked and ensemble averaged over 200 rotor revolutions. The injection holes are located at 61%, 71%, 81%, and 91% blade axial chord, in the tip trench of a single blade with a clearance of 1.40% blade height. Individual injection at 61% and 71% chord reduced the leakage vortex size. Coolant injection at 81% chord was the most successful in reducing the total pressure deficit in the leakage vortex. Injection from 91% chord had no effect on the leakage vortex. Injection from combinations of holes had greater effect in reducing the leakage vortex size and the total pressure deficit associated with the vortex. It can be concluded that the individual jets most likely turn the leakage flow towards the trailing edge. Most of the leakage flow that is responsible for the greatest total pressure deficit occurs around 80% chord.

Original languageEnglish (US)
Title of host publicationProceedings of the ASME Turbo Expo 2004: Volume 5B: Turbomachinery; Axial Flow Turbine Aerodynamics; Design Methods and CFD Modelling for Turbomachinery; Turbomachines and the Environment
Pages1089-1098
Number of pages10
Volume5 B
StatePublished - 2004
Event2004 ASME Turbo Expo - Vienna, Austria
Duration: Jun 14 2004Jun 17 2004

Other

Other2004 ASME Turbo Expo
CountryAustria
CityVienna
Period6/14/046/17/04

Fingerprint

Vortex flow
Turbines
Rotors
Phase measurement
Cooling systems
Coolants
Sensors

All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Rao, N. M., & Camci, C. (2004). Axial turbine tip desensitization by injection from a tip trench part 2: Leakage flow sensitivity to injection location. In Proceedings of the ASME Turbo Expo 2004: Volume 5B: Turbomachinery; Axial Flow Turbine Aerodynamics; Design Methods and CFD Modelling for Turbomachinery; Turbomachines and the Environment (Vol. 5 B, pp. 1089-1098)
Rao, Nikhil M. ; Camci, Cengiz. / Axial turbine tip desensitization by injection from a tip trench part 2 : Leakage flow sensitivity to injection location. Proceedings of the ASME Turbo Expo 2004: Volume 5B: Turbomachinery; Axial Flow Turbine Aerodynamics; Design Methods and CFD Modelling for Turbomachinery; Turbomachines and the Environment. Vol. 5 B 2004. pp. 1089-1098
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abstract = "In Part 1 of this paper it was shown that discrete jets issuing from a tip platform trench were successful in reducing the total pressure deficit due to tip leakage flow. The specific tip cooling system used in Part 1 had all four injection locations active. This paper examines the effect of the individual location of the injection hole on the tip leakage flow. The investigation was carried out in a large-scale rotating rig. Total pressure downstream of the rotor exit was measured using a Kulite sensor. The measurements were phase-locked and ensemble averaged over 200 rotor revolutions. The injection holes are located at 61{\%}, 71{\%}, 81{\%}, and 91{\%} blade axial chord, in the tip trench of a single blade with a clearance of 1.40{\%} blade height. Individual injection at 61{\%} and 71{\%} chord reduced the leakage vortex size. Coolant injection at 81{\%} chord was the most successful in reducing the total pressure deficit in the leakage vortex. Injection from 91{\%} chord had no effect on the leakage vortex. Injection from combinations of holes had greater effect in reducing the leakage vortex size and the total pressure deficit associated with the vortex. It can be concluded that the individual jets most likely turn the leakage flow towards the trailing edge. Most of the leakage flow that is responsible for the greatest total pressure deficit occurs around 80{\%} chord.",
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Rao, NM & Camci, C 2004, Axial turbine tip desensitization by injection from a tip trench part 2: Leakage flow sensitivity to injection location. in Proceedings of the ASME Turbo Expo 2004: Volume 5B: Turbomachinery; Axial Flow Turbine Aerodynamics; Design Methods and CFD Modelling for Turbomachinery; Turbomachines and the Environment. vol. 5 B, pp. 1089-1098, 2004 ASME Turbo Expo, Vienna, Austria, 6/14/04.

Axial turbine tip desensitization by injection from a tip trench part 2 : Leakage flow sensitivity to injection location. / Rao, Nikhil M.; Camci, Cengiz.

Proceedings of the ASME Turbo Expo 2004: Volume 5B: Turbomachinery; Axial Flow Turbine Aerodynamics; Design Methods and CFD Modelling for Turbomachinery; Turbomachines and the Environment. Vol. 5 B 2004. p. 1089-1098.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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N2 - In Part 1 of this paper it was shown that discrete jets issuing from a tip platform trench were successful in reducing the total pressure deficit due to tip leakage flow. The specific tip cooling system used in Part 1 had all four injection locations active. This paper examines the effect of the individual location of the injection hole on the tip leakage flow. The investigation was carried out in a large-scale rotating rig. Total pressure downstream of the rotor exit was measured using a Kulite sensor. The measurements were phase-locked and ensemble averaged over 200 rotor revolutions. The injection holes are located at 61%, 71%, 81%, and 91% blade axial chord, in the tip trench of a single blade with a clearance of 1.40% blade height. Individual injection at 61% and 71% chord reduced the leakage vortex size. Coolant injection at 81% chord was the most successful in reducing the total pressure deficit in the leakage vortex. Injection from 91% chord had no effect on the leakage vortex. Injection from combinations of holes had greater effect in reducing the leakage vortex size and the total pressure deficit associated with the vortex. It can be concluded that the individual jets most likely turn the leakage flow towards the trailing edge. Most of the leakage flow that is responsible for the greatest total pressure deficit occurs around 80% chord.

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Rao NM, Camci C. Axial turbine tip desensitization by injection from a tip trench part 2: Leakage flow sensitivity to injection location. In Proceedings of the ASME Turbo Expo 2004: Volume 5B: Turbomachinery; Axial Flow Turbine Aerodynamics; Design Methods and CFD Modelling for Turbomachinery; Turbomachines and the Environment. Vol. 5 B. 2004. p. 1089-1098