Sound emission of a turbine stage due to an azimuthally periodic mean temperature

Abstract

It is shown in a simulation that the tonal sound emission of a high-pressure turbine stage may increase considerably when the mean temperature of the inflow is spatially not uniform. The tonal sound power emitted in the downstream direction is increased by 5.9 dB at the blade passing frequency f b and by 11.7 dB at [Formula: see text]. The mean total temperature of the incoming flow is assumed to vary periodically in the azimuthal direction with a temperature amplitude of ±9% as a result of 14 discrete burners inside the annular combustion chamber. The temperature also varies radially with minima at the inner and outer walls of the annular channel. The turbine stage consists of a stator with 70 vanes and a rotor with 73 blades, while the temperature field in the simulation has 14 periods in the circumference.