Noise predictions of the advanced noise control fan model using lattice Boltzmann method and Ffowcs Williams-Hawkings analogy

作者：Marcondes Orselli R; Souza Carmo B; Lauterjung Queiroz R

来源：Journal of the Brazilian Society of Mechanical Sciences and Engineering, 2018, 40(1): UNSP 34.

DOI：10.1007/s40430-018-0982-2

• Fan noise
• Computational aeroacoustics
• Lattice Boltzmann method
• Acoustic analogy
• Computational fluid dynamics

The lattice Boltzmann method (LBM) is applied to simulate the complete three-dimensional transient flow and noise generated on the Advanced Noise Control Fan (ANCF) geometry. The ANCF is a model developed by NASA Glenn composed by a rotor-stator system enclosed by a duct. The experimental noise spectra provided by NASA at 30 microphones around the fan are used to validate the results obtained with the LBM. Overall, the predicted sound spectra pattern and the main tonal frequencies agree well with the noise measurements; in terms of tonal noise levels, the agreement varies depending on the frequency and microphone position. The noise at the 30 microphone positions is also computed by employing the porous Ffowcs Williams and Hawkings (FW-H) formulation with noise sources located on two integral surfaces placed at the ANCF openings. The good agreement obtained between the sound levels calculated with the FW-H formulation and those computed by the LBM show that the FW-H analogy may be applied in place of the LBM numerical simulation. In addition, the FW-H formulation is applied to compute the sound generation with sources located on different physical surfaces of the ANCF model such as the rotor, stator, hub, and nacelle, procedure known as noise source breakdown. A comparison of the FW-H results applied on different surfaces of the ANCF model with the noise computed by the LBM shows that most of the tonal noise levels observed at the far-field microphones (predicted by the LBM simulation) correspond to the noise sources generated on the stator vane surfaces. Such a study of the noise sources breakdown also evidences the interaction effect between the rotor and the stator, whose mechanism is the main contributor to the tonal noise generation content.

• 出版日期2018-1