基于弱可压DCS的汽车侧窗连动风振噪声研究与优化

发布时间：2018-03-09 12:18

本文选题：汽车风振噪声　切入点：连续开启　出处：《湖南工业大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着我国高速通车里程的延长,以及城市群路网的不断发展为人们的出行带来极大的便利。与此同时,由于长时间高速行车中仅靠内循环进行通风换气,会因缺乏新鲜空气而造成乘员头晕、精神不振等不适。开启汽车侧窗或天窗必然引起风振噪声,当风振噪声的脉动压力频率与人体固有频率接近时,亦会产生空腔共鸣,加剧引发耳鸣、心慌、头晕等不舒适感。为追求更高的出行质量,满足人们对车辆乘坐舒适性的需求,预估分析车窗开启下汽车最大风振噪声产生机理和精确开度,并运用必要手段控制风振噪声显得尤为重要。目前国内外静态工况的汽车风振噪声仿真计算已经取得诸多进展,为进一步探究风振噪声形成机理并获得汽车最大风振噪声的精确侧窗开度,需要对侧窗连续开启工况进行仿真模拟计算,而现有基于有限元法的数值模拟技术对动边界计算时存在网格质量、计算精度不足等问题。因此,本文通过结合实车道路试验、风洞试验和基于弱可压DCS方法,探讨了汽车侧窗连续开启工况下的风振噪声产生机理和侧窗精确开度,在此基础上,通过添加附加装置等措施,进行了降噪优化,取得了较好的效果。主要研究内容如下:1.对某款车型进行了实车道路试验,以乘员耳边位置为监测点,探究了驾驶员左耳、右耳、后排乘客左、右处监测点和在车窗关闭时、左前窗和左后窗不同开度工况下的声频特性分析。2.针对侧窗连续开启下的风振噪声计算,考虑空气介质的可压缩性,将弱可压缩模型与声学计算方法DCS结合,应用于简易车厢风振噪声计算,通过对比发现其数值仿真结果与试验结果较为接近,证明了基于弱可压模型DCS方法在研究风振噪声问题上的准确性。3.运用弱可压DCS方法对某款实车模型的侧窗风振噪声机理及连续开启工况风振噪声特性进行了研究。通过分析车内流场和压力分布,阐述了汽车侧窗风振噪声的产生机理。4.提出了实时开度等效替代法对计算结果进行声学后处理,获得了声压级连续开度变化曲线,探明了汽车左前侧窗和左后侧窗最大风振噪声对应的侧窗开度,分别为318mm和282mm。5.根据风振噪声产生机理、仿生学以及最大风振噪声侧窗开度,添加侧窗降噪装置,在后侧窗前沿B柱处设计仿生可降噪沟槽进行降噪,并采用多岛遗传算法进行寻优,实现降噪2d B,效果较好。
[Abstract]:With the extension of high-speed mileage and the continuous development of urban agglomeration network, it brings great convenience for people to travel. The lack of fresh air will cause dizziness and mental infirmity of the crew. Opening the side window or skylight of a car will inevitably cause wind-induced noise. When the pulsating pressure frequency of the wind-induced noise is close to the natural frequency of the human body, the cavity will also resonate. In order to pursue higher travel quality and meet people's demand for ride comfort, it is estimated that the mechanism and accuracy of the maximum wind-induced noise produced by the car under the opening of the window will be analyzed. It is particularly important to use necessary means to control wind-induced noise. At present, many progress has been made in the simulation calculation of wind-induced noise of vehicles under static working conditions at home and abroad. In order to further explore the formation mechanism of wind-induced noise and obtain the accurate opening degree of the automobile maximum wind-induced noise, it is necessary to simulate and calculate the continuous opening condition of the side-window. However, the existing numerical simulation technology based on finite element method has some problems such as mesh quality and insufficient calculation precision. Therefore, this paper combines road test, wind tunnel test and DCS method based on weak compressibility. In this paper, the mechanism of wind-induced noise and the precise opening of side window under continuous opening of side window are discussed. On the basis of this, the noise reduction is optimized by adding additional devices and other measures. The main contents of this study are as follows: 1.A real road test was carried out on a certain type of vehicle, and the driver's left ear, right ear, rear passenger left, right side monitoring point and when the car window was closed were investigated, taking the position of the occupant's ear as the monitoring point, the driver's left ear, the right ear, the rear passenger's left side, the right side of the passenger, and when the car window was closed, Analysis of audio frequency characteristics of left front window and left rear window under different opening conditions .2. considering the compressibility of air medium, the weak compressible model is combined with the acoustic calculation method DCS for the calculation of wind vibration and noise under the continuous opening of the side window. Applied to the calculation of wind-induced noise of the aircarriage, it is found that the numerical simulation results are close to the experimental results. The accuracy of the DCS method based on the weak compressible model in the study of wind-induced noise problem is proved. 3. The wind-induced noise mechanism of a real vehicle model and the wind-induced noise characteristics under continuous opening condition are studied by using the weakly compressible DCS method. By analyzing the flow field and pressure distribution inside the vehicle, In this paper, the mechanism of wind-induced noise of side windows is described. Finally, the acoustical post-processing method of real-time equivalent opening substitution method is put forward, and the continuous opening curve of sound pressure level is obtained. The lateral window opening corresponding to the maximum wind vibration noise of the left front side window and the left rear side window is found out, which is 318mm and 282mm .5.According to the wind-induced noise generation mechanism, the bionics and the maximum wind-induced noise lateral window opening degree, the lateral window noise reduction device is added. A bionic noise-reducing groove is designed at the front B column of the rear side window to reduce the noise, and the multi-island genetic algorithm is used to optimize the noise. The noise reduction is achieved by 2dB, and the effect is good.
【学位授予单位】：湖南工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.835

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