Controle ativo de ruído aplicado a dutos com propagação de modos acústicos de alta ordem via particionamento axial

Abstract

The active noise control (ANC) applied to ducts where there is the propagation of plane waves has been the subject of several studies. In these cases applies the single-channel active control. The ducts with large cross sections, the acoustic propagation occurs in the presence of highorder modes. For these ducts is necessary to use multichannel control, which leads the ANC system to use many sensors and actuators, resulting in a very complex project. This work seeks to apply a methodology of changing the geometry of large ducts, to ensure the propagation of plane waves within them and thus use only a single-channel ANC system. The strategy is to divide the large cross section of the duct into smaller areas to ensure plane waves in the frequency band of interest. Several techniques and tools have been used, such as simulations of the acoustic system, Hybridized Genetic Algorithm and the FxLMS algorithm for the development of control system design. A large duct was built and instrumented. In addition, an electronic board control with Digital Signal Processor (DSP) was used to run programs in the ANC system in real time. We obtained significant attenuation of noise levels, which makes the active control developed promising for industrial applications.