Measurement of thermal wakes in compressor secondary air systems using low frequency thermocouple data

Experimental temperature measurements are made using two Datatel radio telemetry systems with K-type glass insulated thermocouples inside the Sussex Multiple Cavity Rig (MCR). Currently the MCR supports independent rotational control of both the rotor (disc pack) and a central shaft. The results presented here highlight a novel application whereby the wakes of a set of rotating blocks are captured whilst the rig is at full speed using low frequency data acquisition. This takes advantage of the relative motion of the two telemetry systems to look at flow structures that are usually outside of the frequency domain of the instrumentation.