This paper describes an experiment on a GHH BORSIG Type THM 1304-10 Gas Turbine engine to test the effects of variable vane setting on the vibration behaviour of the blades in all 10 stages of the axial compressor. The rotor was fitted with a network of strain-gauges. An analogue telemetry system was arranged using standard hardware and special application software to display in real-time and to log the full range of frequencies and amplitudes for all instrumented blades. The data acquisition system is described together with a presentation of the live display which allowed engineers to interact with measured results to maximise the benefits of the test whilst all strain-gauges were still functional. Tests were arranged to maximise the vibration data collected at all points before gauge mortality was experienced. Prior to the test, blades were vibrated statically to determine shapes of the first four vibration modes. The paper discusses the fixing techniques for the gauges, the modal shape measurement technique and the calibration of the strain-gauges. The telemetry system architecture and multiplexing arrangement are described together with examples of typical test data and the conclusions concerning the effects on blade vibration of different variable inlet guide vanes (IGV) settings.

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