Simulations on Active Fan Noise Control

Overview & Synopsis

Noise reduction by active noise control in jet engines and its prediction is of high interest, since the acoustic goals of flightpath 2050 can hardly be achieved by passive acoustic treatments. Numerous former test campaigns showed that significant noise reduction is possible by active noise control. Simulations are needed for further understanding of test results and in order to predict the noise reduction and possibly impact on the performance of future jet engines. Therefore an ANC prediction tool in frequency domain based on a common 3D CAA solver has been developed. The tool is validated by measurements in a simple straight duct with wall mounted sensors and loudspeakers. The primary sound field has one dominant azimuthal mode order. Varying complexity of the control concept leads to significant distinct results in noise reduction and the input signals of control sources. Later application of the tool will be the simulation of jet engines (i.e. inlet, fan, stator and nozzle). The CAA solver does not include the rotation of fan. Established models of fan scattering and sound transmission need to be implemented. The effect of the fan models on the noise control can be assumed by means of the investigated control concepts.