Conference_programme: 19.1 - Duct Acoustics
Lecture: Acoustic study of different mufflers based on metamaterials using the black hole principle for aircraft industry
Author(s): Deaconu Marius, Radulescu Dan , Vizitiu Georgel
Summary:
Noise reduction in aviation industry is a major problem that led to numerous research papers and projects mainly focused on the noise generated by the engines. One of the most studied solutions for in duct noise consists in reactive structures of the acoustic liner types, which dissipates the acoustic energy in the neck of micro-perforations of a panel (MPP). In this paper a different approach for duct noise reduction is adopted which consist in metamaterials that lead to a so-called acoustic black hole effect ABH. This term is relatively new and researches of acoustic properties of metamaterials in ducts were made but only from acoustic point of view. Taking into account that the pressure loss is sensible even at small perforations, designing of such metamaterial in aviation industry must take into account this aspect. Existing studies of mufflers using metamaterials and ABH principles were carried out just from the acoustic point of view. In this paper we shall consider the mean flow effect on acoustic attenuation. In this study, several designs for the muffler are proposed to be studied. The comparison of the designs is performed using numerical CFD and FEM simulations to calculate acoustic attenuation and pressure loss resulted, considering a duct with mean flow. In order to decrease the pressure loss caused by the perforated section we also propose a novel noise solution which consists in a MPP placed in this section, to reduce the pressure loss, and in the back cavity a structure with ABH effect is placed. Using the MPP an additional absorption will appear caused by the visco-thermal losses.\n \n
Corresponding author
Name: Mr Marius DEACONU
e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Country: Romania
