Development of the Larzac Engine Rig for Compressor Stall Testing

The development and upgrade of test installations, instrumentation and the data acquisition system of an existing turbofan engine test rig are described for an experimental program which was planned and initiated to investigate the transient unsteady operation of gas turbine engines with an emphasis on compressor operation. The objective of the program was to examine aerodynamic instabilities such as stall and surge. Of particular interest were the pre-stall behaviour of the compressor and the generation and the detection of gas-path stall/surge precursors. Methods used to invoke compressor stall/surge and to detect stall/surge precursors are described and examples of results of the observed stall/surge phenomena and their precursors are included. However, the precursor pressure pulses are of small amplitude and occur only several milliseconds prior to the point of stall initiation. Additional work is required to incorporate these results in a practical stall warning device.