Fan noise predictions using scale-resolved, statistical, stochastic and semi-analytical models

Abstract

The recently concluded EC FP7 IDEALVENT project has seen the application of a variety of simulation methods by the consortium partners to an industrial blower unit such as used in aircraft Environmental Control Systems. The blower was subjected to different inflow conditions in order to better comprehend the importance of installation effects, and assess the capabilities of the proposed numerical tools to quantify those effects. The prediction tools include scale-resolved, statistical, stochastic and semi-analytical approaches. The predicted acoustic fields were validated by comparison with experimental data obtained on a dedicated test rig, permitting the necessary decontamination of the microphone signals from the reflections at the duct terminations, and turbulent boudary layer related pseudo-sound. A quite good agreement was found between the predicted and measured acoustic data. The tools showed also a good potential for estimating installation effects. Finally, the paper demonstrates the benefits of applying different methods, characterized by different modelling assumptions, for a more thorough understanding of the sound generation mechanisms.