【作者】 李金库；

【导师】 于建国；

【作者基本信息】 东北林业大学 ， 载运工具运用工程， 2012， 博士

【摘要】 随着汽车工业的快速发展,汽车发动机进气噪声已成为影响汽车噪声的主要噪声源之一。交通车辆数量的日益增多而带来的环境污染问题已成为影响居民生活、威胁公众健康的一大公害。目前,人们对排气噪声的控制研究比较多,对进气噪声的研究还不够深入,进气噪声已成为汽车噪声控制的重点对象。因此,深入地研究进气消声系统已经成为当前亟待解决的问题。根据长安杰勋JL486Q1型汽车进气噪声大的特点,应用三维/一维耦合技术设计合理的进气消声器,可为今后消声器的设计与改进提供参考,同时,可以在产品的设计阶段预测消声器的性能和传递损失,检验安装谐振器后对发动机的动力性、经济性的影响,可大大缩短产品的研发周期,降低产品成本。本文以网格生成软件GAMBIT.发动机仿真软件GT-POWER、专业声学软件SYSNOISE和流体动力学软件FLUENT为平台,综合运用有限元法、边界元法、有限体积法等方法对基本消声单元的声学性能、流场进行了数值仿真分析。在分析进气噪声产生的机理和Helmholts肖声原理的基础上,应用声学有限元法分析了Helmholts皆振腔的形状、体积,连接管的喉口尺寸,主管尺寸等不同结构参数对消声器性能的影响,得出了谐振频率和消声量的关系式；应用GT-POWER、FLUENT软件,结合有限体积法,根据该型车汽油机的相关参数,建立了发动机模型以及发动机与进气谐振器的联合模型,描述了在发动机工作状态下消声器的流场分布,分析了安装谐振器以后,发动机动力性、经济性、进气量以及进气效率等变化情况；基于有限元和边界元(BEM/FEM)理论,利用GAMBIT. FLUENT中的NASTRAN和SYSNOISE软件建立谐振器的声一固耦合模型,研究了谐振器的表面位移响应及辐射声场的变化,分析了谐振器壳体厚度、结构阻尼(材料)等因素变化对声场的影响；应用上述研究成果,利用塑料成型技术加工了长安杰勋轿车进气谐振器,针对设计的消声器进行实验研究,分别进行了发动机性能测试实验、汽车底盘测功机噪声实验和道路噪声实验。仿真分析和实验研究结果表明：谐振腔的结构参数对其共振频率有直接的影响。谐振腔的消声峰值主要集中在400Hz以内的低频区域,随着谐振腔体积增大,消声峰值向低频移动,体积相同时,谐振频率不变,和腔体的高度或面积的变化无关,谐振器消声量不随体积的增大而增大,呈现无规律的变化；喉口直径、长度不同,谐振频率不同,直径越大,谐振频率越大,长度越大,谐振频率向低频移动；发动机进气噪声主要集中在138Hz、276Hz、366Hz的三个频率点处,安装消声器后,三个频率点处的进气噪声都有不同程度的下降,最大降幅达7.5dB,车外行驶加速噪声实验表明,整车噪声由89.1dB下降到83.6dB,降幅达5.5dB,为下一步继续降噪奠定了基础；发动机的功率、燃油消耗量、进气量以及进气效率与原车相比没有明显变化,平均误差在5%以内。说明所建立的仿真模型能够很好地预测消声器和发动机的性能指标。本文通过理论分析和试验验证,创造性提出了谐振腔—喉管体积比与谐振频率、消声量的关系特性,谐振频率与谐振器体积的换算关系、主管直径的变化与消声量的关系；找到了最大噪声的频率范围；利用发动机软件、CFD软件及声学软件,应用三维／一维耦合技术,解决了流场、声场和谐振器之间的耦合匹配问题。更多还原

【Abstract】 With the car industry developing rapidly, the intake noise of car’s engine has become one of major noise sources on the impact automobiles noise. Environmental pollution problems brought by more and more traffic vehicles have become a large hazards affecting residents living,threatening to public health. At present,the study about exhaust noise control for more,else,the intake noise not enough,the intake noise has become the focus of noise control. Thus,studying into the intake noise reduction system deeply has become a burning question.According to the characteristic of the larger intake noise for Chang-an Jiexun JL486Q1type car,that applying to three-dimensional/one-dimensional coupling technology and designing reasonable intake muffler may supply the reference for the design and improvement to the muffler in the future. At the same time,It may predict performance and transmission loss of the muffler at the product design stage,inspect the influence to dynamics and economy of engine after the resonator installation,it can greatly shorten the product development cycle and reduce the product cost.This paper bases on the mesh generation software GAMBIT,engine simulation software GT-POWER,professional acoustic software SYSNOISE and fluid dynamics software FLUENT as platform,through comprehensively using finite element method,boundary element method,finite volume method and so on,to simulate and analyze the acoustic performance for the basic noise reduction unit and flow field.on the basis of analyzing about the mechanism by intake noise generating and Helmholts noise reduction principle, applying to acoustic finite element method to analyze different structure parameters,which include the shape,volume, throat size,mian tube of the resonator on the influence of the muffler performance, concluding the mathematical expressions for resonant frequency;Applying to the softwares for GT-POWER,FLUENT,combined with finite volume method,according to the related parameters of the gasoline engine for JL486Q1type,the engine model together with the joint model of the engine and the intake resonator is established,and describing the muffler flow field distribution under the condition of engine working,analyzing the changing circumstances to the engine power,engine economy,air inflow and air intake efficiency after the resonator installation.Based on the finite element and boundary element (BEM/FEM)theory,using GAMBIT,NASTRAN for FLUENT and SYSNOISE software to establish the sound-solid coupling model for (?)esonator,studying the surface displacement response for the resonator and the change for (?)ound field radiation,analyzing the influence on the acoustic field because of the change factors of the resonator shell thickness and structure damping (material);with the application of the research results,using the plastic molding technology,processing the intake resonator of chang- an Jiexun car,and doing the experimental research for the designed muffler. The engine performance test,the vehicle chassis dynamometer noise experiments and road noise experiment had been done.Simulation analysis and experimental results show that the resonant structure parameters have a direct effect on its resonant frequency.Resonant cavity peak for noise reduction mainly concentrates within400Hz in the low frequency region,the resonant cavity increases in volume,the noise reduction peak moves to the lower frequency,if the volume is the sameness,the resonant frequency, which has nothing to do with the change for the height and area of the cavity,is not changed. Noise reduction amount of resonant cavity is not enlarged as the volume increases, which is no rule.As the throat diameter and its length varies,the resonant frequency is different, and the greater the diameter, the greater the resonant frequency,the greater the length,the resonant frequency moves to the lower frequency; Engine intake noise mainly focuses on the three frequency points,138Hz,276Hz,and366Hz.The intake noise of which has different degree in the fall after the muffler installation, the largest decline for7.5dB(A),the experiment of acceleration driving indicates that the vehicle noise outside declines from89.1dB(A) to83.6dB(A), the largest decline for5.5dB(A),which lays the foundation for the noise reduction in next step. Engine power, fuel consumption,air inflow and air intake efficiency do not change obviously compared with the original car,the mean error is less than5%.This illustrats that the model can predict the performance index of muffler and engine well.In this paper,through theoretical analysis and experimental verification,the relationship characteristic between the volume ratio for the cavity with neck tube and noise reduction amount,the resonant frequency, the conversion relationship between the resonant frequency and the resonator volume, main tube diameter and the noise reduction, and so on,have been put forward creatively;The frequency range for the greatest noise has been found;Using the engine, CFD and acoustic softwares, as well as three-dimensional/one-dimensional coupling technology,the coupling and matching problem among the flow field,the acoustic field and the resonator have been solved.更多还原