Desarrollo e implementación de herramientas numéricas basadas en Ansys para la simulación acústica de dispositivos de control de ruido en vehículos. Aplicación a silenciadores de escape reactivos
[EN] The present postgraduate dissertation carries out the parametrization of silencers in different shapes and sizes w ith the aim of speeding up the work and the analysis of their acoustic behaviour . Finite element p rograms such as Ansys APDL allow us to carry out tests that are very accurate an...
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| Tipo de recurso: | tesis de maestría |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | español |
| OAI Identifier: | oai:riunet.upv.es:10251/74621 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/74621 |
| Access Level: | acceso abierto |
| Palabra clave: | Elementos finitos Acústica Silenciadores reactivos Control de ruido Ansys Lenguaje paramétrico. INGENIERIA MECANICA Máster Universitario en Ingeniería Mecánica-Màster Universitari en Enginyeria Mecànica |
| Sumario: | [EN] The present postgraduate dissertation carries out the parametrization of silencers in different shapes and sizes w ith the aim of speeding up the work and the analysis of their acoustic behaviour . Finite element p rograms such as Ansys APDL allow us to carry out tests that are very accurate and powerful and are commonly used in companies . However, the lack of a suitable graphical interface involves a tedious work with the possibility of making errors that will cause an increase in the calculation times and therefore reduce the quantity of the possible analysis to be carr ied out. Fortunately , Ansys APDL allows to import m acros which can parameterize these silencers, so that, once the macros are carried out, it will only be necessary to change the value of the geometries and to call the function. The research group to which this Master’s Thesis belongs has a wide experience in the modeling and experimental characterization of the acoustic behavior of the exhaust system of internal combustion engines. In the past few decades, exhaustive work has been carried out in relation to the development, implementation and validation of computational tools based on three - dimensional analytical solutions of the wave equation to reduce the computational cost, although th e validity of this approach is only possible with relatively simple configurations from a geometrical perspective [1 - 6]. In order to eliminate these geometrical limitations, the research group has also devoted special attention to the development of general tools based on the finite element method to consider more complex cases, for example, the presence of high temperatures , thermal gradients and mean flow [7 - 9] . Given the high computational cost of the numerical techniques such as the Finite Element Method [10] , it is important to develop analytical and numerical hybrid models which would reduce the aforementioned computati onal effort in the study of complex cases [11,12] . While the acoustic attenuation is determined largely by the mufflers of the exhaust line, other devices such as catalysts and particulate filters also have a significant influence. For this reason, models and tools have been developed for proper acoustic characterization of such devices in previous years [13 - 15] . UNIVERSITAT POLITÈCNICA DE VALÈNCIA D EPARTAMENTO DE I NGENIERÍA M ECÁNICA Y DE M ATERIALES M ÁSTER EN I NGENIERÍA M ECÁNICA 10 Firstly, this thesis will briefly expand on acoustic theory and the more relevant variables. Also, the application of acoustic theory to determine the acoustic attenuation of the silencers, the types of silencers and their performance . Furthermore, this thesis will provide some information related to the acoustic propagation phenomenon in circular pipes and the behavior of the transversal modes in t he silencers. Later, we will continue with the operation of the program Ansys APDL, including a brief description in order to know how this program works and a tutorial to explain the operation of one of the macros carried out in this thesis and also how t hey have been implemented. The study and analysis of the attenuation curves of different silencers and for a number of geometries will be place d in a specific section together with the analysis of the cutoff frequency and the comparative of results obtain ed in Ansys with those obtained by Math c ad. However, it has not been possible to carry out this comparison for all types of silencers. On the other hand, in the case of the simple c hamber , it has been possible to calculate the frequencies of maximum TL and pass band s . With the aim to be more consistent with our results, the geometry of each silencer has been checked by means of the program Comsol Multiphysics. Previously a small introduction to the program will be presented and the procedures used to calcul ate the attenuation of a silencer with Comsol Multiphysics will be discussed . Finally, some general conclusions of the work will be presented and the possible applications in the future will be briefly described . Key words: finite elements, acoustic, react ive silencers, Ansys, parametric language. |
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