【作者】 贾维新；

【导师】 郝志勇；

【作者基本信息】 浙江大学 ， 动力机械及工程， 2008， 博士

【摘要】 为了促进发动机振动噪声研究水平的提高,特别是为了深化数字化仿真技术在发动机及整车的振动噪声控制方面的应用,推动数字化仿真技术在该领域的应用向更深、更广的层次迈进,本文对发动机振动噪声测试方法、数字化仿真方法、先进的结构优化设计方法进行了深入细致的研究,并研究了具有企业实际意义的应用问题。系统地进行了发动机噪声源识别方法的研究,发展了表面振动速度法,增加了两类零件声辐射比的理论计算方法,介绍了声强测量法在发动机声功率预测和噪声源识别中的应用。提出了一种既高效又满足一定精度的多体动力学—有限元法—声学分析法相结合的发动机零部件NVH性能预测方法,验证了该方法的准确性,并研究了该方法在发动机机体低噪声设计中的应用。以发动机油底壳为例,对发动机上的罩壳类零部件振动噪声预测中涉及的关键问题进行研究,如密封垫或隔振挚边界条件的处理,结构与流体的流固耦合分析方法等,提出了对复杂非线性边界条件进行处理的“线性简化边界法”,并对比了两种流固耦合法,为此类零件的NVH性能设计提供准确可靠的数字化仿真方法。阐述了进气系统噪声产生的根源及进气系统设计中要考虑的问题,对进气系统气动噪声三维仿真中的边界条件,即进气系统的线性化声源特性的提取方法进行了详细研究,对实验最小二乘法、一维有限体积法、圆形活塞辐射器假设法,这三种线性声源提取方法进行了对比验证及分析,完善了进气系统设计不同阶段的三维仿真边界条件的获取方式。结合实验验证,研究了提高进气系统声学性能预测准确性的方法,另外系统地研究了发动机进气系统设计中进气口气动噪声、结构辐射噪声、空气动力学及结构模态等特性的数字化仿真方法,为进气系统声学和空气动力性能设计提供了整体的数字化解决方案。从现代设计角度出发,研究将结构优化技术应用到发动机机体轻量化设计和油底壳低噪声设计中。在单缸机缸体轻量化设计中引入了拓扑优化和形状优化方法;在低噪声油底壳设计中引入了形貌优化方法,为优化技术在发动机复杂零部件设计上的应用进行了探索。本文为发动机振动噪声设计水平的提高和发展,进行了开拓性的工作,发展和完善了发动机现代设计理论和方法,取得了一系列具有工程实用价值的成果。更多还原

【Abstract】 In order to enhance the level of study on the noise and vibration, especially to deepen the application of numerical simulation technique to the engine and vehicle noise and vibration control, and promote the application of numerical simulation technique to a broader and deeper degree in this research domain, this dissertation mainly focused on the following items in depth and meticulous: the study on engine noise and vibration test method, numerical simulation method, advanced structural optimization, which also involved the applicable engineering problems with actual significance for the enterprises.Systemic study on the method of engine noise source identification was performed in this dissertation, which included the evolution of the vibration velocity method, the supplement of two theory of noise radiation ratio respectively for two types of component, the introduction of the application of sound intensity to the prediction of engine sound power level and identification of noise source.An integrated numerical simulation method was proposed, which comprised of the multibody-dynamic method, finite element method and acoustic simulation method. The comparison of the test result and predicted results validated the precision of this method, and testified the high prediction efficiency. And the application of the integrated method to the low noise engine block design was studied.Taking the engine oil pan as example, the key points in the numerical simulation of noise and vibration for cover-type components was studied, for example the treatment of boundary condition attached with grommet and gasket, the simulation measures of structure and fluid coupling. A new method, namely "Boundary condition linear simplification method" was proposed for the NVH performance simulation of the component, which has complex boundary condition, and two structure-fluid coupling methods were compared. All of these studies supplied actual and reliable numerical simulation approach for the NVH performance of cover-type components.The root of how the intake system noise is caused and the requirement of intake system design were illustrated. The boundary condition used in the 3D simulation of intake system snorkel noise actually is the linear source characteristic, in this dissertation, the determination measures of the linear source characteristic, which included least square method, 1D finite volume method and round piston radiator hypothesis method, were studied, also making a comparative analysis and validation for these three methods. Which make up the extracting methods for boundary condition of intake system snorkel noise 3D simulation at different design phases. Moreover, the method to improve the accuracy of acoustic performance simulation of intake system was studied assisted by the test validation. In addition, the studies included the simulation method of snorkel noise, structural radiation noise, CFD performance and structure modal, which supplied an integrated numerical solution approach for the acoustic and aerodynamics performance of intake system.At last, from the viewpoint of numerical design, the application of structural optimization to the engine block light-weight design and oil pan low noise design was attempted, the topology optimization and shape optimization were involved in the single cylinder engine block light weight design; and the topography optimization was involved in the low noise oil pan design, which explored a path for the application of structure optimization technique to the engine complex components.The studies in this dissertation are pioneering, which has a significant promotion for the enhancement and development of engine low noise and vibration design. It evolves and improves the theory and method of modern design for I.C. engine, and achieves several productions with great engineering application value.更多还原