Impact of the turbulence modeling approach on the accuracy of the fan noise level prediction

Abstract

The fan is the dominant source of noise for modern high bypass ratio aircraft engines. The article presents the results of investigating the influence of the approach to modeling the turbulence in modeling fan stage noise generation on the results of noise level prediction. Numerical investigation was performed for a model fan stage in test conditions in an anechoic chamber. Basic operating modes determining the acoustic performance of the fan were used. Calculation of far-field noise was performed using finite element modeling on the basis of the modal composition of generated noise. The influence of the turbulence model on the number and amplitude of acoustic modes excited in the flow on the fundamental frequency harmonics was analyzed. It is shown that modeling of the anisotropic flow turbulence in calculating non-stationary rotor-stator interaction makes it possible to obtain results close to the experimental ones.

Keywords

• bypass turbojet engine
• fan
• rotor-stator interaction
• turbulence
• acoustic modes
• sound pressure level
• numerical modeling