Axial turbine tip desensitization by injection from a tip trench: Part 1: Effect of injection mass flow rate

Nikhil M. Rao, Cengiz Camci

Research output: Contribution to conferencePaper

30 Citations (Scopus)

Abstract

An experimental study of a turbine tip desensitization method based on tip coolant injection was conducted in a large-scale rotating turbine rig. One of twenty-nine rotor blades was modified and instrumented to have a tip trench with discrete injection holes directed towards the pressure side. Time accurate absolute total pressure was measured 0.3 chord lengths downstream of the rotor exit plane using a fast response dynamic pressure sensor in a phase-locked manner. The test cases presented include results for tip gap heights of 1.40% and 0.72% of the blade height, and coolant injection rates of 0.41%, 0.52%, 0.63%, and 0.72% core mass flow rate. At a gap height of 1.40% the leakage vortex is large, occupying about 15% blade span. A reduction in gap height causes the leakage vortex to reduce in size and move towards the blade suction side. The minimum total pressure measured, for the reduced gap, in the leakage vortex is about 4% greater. Coolant injection from the tip trench is successful in filling in the total pressure defect originally resulting from the leakage vortex without injection. At the higher tip injection rates the leakage vortex is also seen to have moved towards the blade tip. The high momentum associated with the tip jets affects the total pressure distributions in the neighboring passages.

Original languageEnglish (US)
Pages1075-1088
Number of pages14
StatePublished - Dec 22 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
Flow rate
Coolants
Rotors
Pressure sensors
Pressure distribution
Turbomachine blades
Dynamic response
Momentum
Defects

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 1: Effect of injection mass flow rate. 1075-1088. Paper presented at 2004 ASME Turbo Expo, Vienna, Austria.
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Rao, NM & Camci, C 2004, 'Axial turbine tip desensitization by injection from a tip trench: Part 1: Effect of injection mass flow rate' Paper presented at 2004 ASME Turbo Expo, Vienna, Austria, 6/14/04 - 6/17/04, pp. 1075-1088.

Axial turbine tip desensitization by injection from a tip trench : Part 1: Effect of injection mass flow rate. / Rao, Nikhil M.; Camci, Cengiz.

2004. 1075-1088 Paper presented at 2004 ASME Turbo Expo, Vienna, Austria.

Research output: Contribution to conferencePaper

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