Utilização de síntese modal de componentes e particionamento axial de dutos para controle dos modos acústicos de alta ordem

• Ano de defesa: 2009
• Autor(a) principal: Nunes, Maria Alzira de Araújo
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Uberlândia; BR; Programa de Pós-graduação em Engenharia Mecânica; Engenharias; UFU
• Palavras-chave em Português: Controle ativo de ruído; Modos de alta ordem; Síntese modal de componentes; Otimização; Controle de ruído; Active noise control; Higher order duct mode; Component mode synthesis; Optimization; CNPQ::ENGENHARIAS::ENGENHARIA MECANICA
• Link de acesso: https://repositorio.ufu.br/handle/123456789/14680

In this study, the proposal of this work is centered in the noise reduction in ducts that became, over the years, a field of intense application. The traditional approach to acoustic noise control in ducts uses passive techniques and fixed reactive silencers to mitigate the noise. In this moment, the Active Control of Noise (ANC) is an attractive approach to noise reduction, because this type of treatment shows efficient, mainly, low frequencies. Through of the potential of the implementation of the ANC in ducts, where there are propagation of modes of high order, in this work, proposes the internal partitioning of the duct (in the axial direction) so that the active control of noise is carried out in regions spread flat sound waves. The methodology of work is composed of modeling and numeric simulation of the active control of noise, using the technical Component Modal Synthesis (CMS), considering tonal noise and broadband noise. Firstly, a theoretical study is realized through of methods of analytic control based in the decrease of cost functions, such as the pressure in a point within of the duct, the acoustics potential energy and the total acoustics potency in the duct. The results are displayed to show the behavior and efficiency of the ANC in ducts with flat waves and modes of high order. The use of internal partitions in the duct to planning of the sound waves is validated using a numeric model of finite elements. After validation, the model of duct proposed is modeled using CMS, with an optimizer of the actuator position. Therefore, results optimized showed that for a tonal noise, obtain mitigation of the order of 22 dB depending of the frequency of interest, using single channel system. For the noise of the type broadband, get mitigation of the order of 15 dB, nevertheless, with system of control of the type multichannel. Furthermore, advantages of the internal partitioning of the duct for active control of noise are studied and shown over the work.