It is difficult to make a reliable measurement of running clearance in the hostile environment over the blading of a modern gas turbine. When engine manufacturers require the measurement to be made over every blade during live engine tests, system reliability, ruggedness, and ease of operation are of primary importance. This paper describes a tip clearance measurement system that can measure clearance over every blade around a rotor. The measurement system concept is presented, and the system design described in detail. Commissioning of the measurement system on a compressor test facility, and the results obtained are discussed. An analysis of system performance during the commissioning trials concludes the paper.

Issue Section:
Gas Turbines: Controls and Diagnostics
Topics:
Blades, Clearances (Engineering), Gas turbines, Measurement systems, Engines, Compressors, Design, Reliability, Rotors, Systems analysis, Test facilities
1.
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2.
Chivers, J. W. H., 1989, “A Technique for the Measurement of Blade Tip Clearance in a Gas Turbine,” AIAA Paper No. 89-2916.
3.
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4.
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5.
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6.
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8.
Sheard, A. G., and Palmer, A. A., 1993, “Miniature Traverse Actuator for Mapping the Flow Field Between Gas Turbine Blade Rows,” Proceedings of the 3rd I.Mech.E Machine Actuators and Controls, pp. 1–11.
9.
Sheard
A. G.
,
Westerman
G. C.
,
Killeen
B.
, and
Fitzpatrick
M.
,
1994
, “
A High-Speed Capacitance-Based System for Gaging Turbomachinery Blading Radius During the Tip Grind Process
,”
ASME JOURNAL OF ENGINEERING FOR GAS TURBINES AND POWER
, Vol.
116
, pp.
243
–
249
.
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 by The American Society of Mechanical Engineers
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