车用交流发电机气动噪声特性分析与降噪研究

发布时间：2018-04-13 19:19

本文选题：风扇 + 交流发电机　；参考：《西南交通大学》2014年硕士论文

【摘要】：车用交流发电机是通过皮带轮连接发动机将机械能转化为电能的装置,随着转速的提高,气动噪声成为交流发电机噪声中越来越重要的组成部分。研究交流发电机气动噪声的特性及降噪方法具有重要的意义。针对交流发电机气动噪声问题,本文建立交流发电机气动噪声的计算方法,研究分析主要气动噪声源部位的远场辐射气动噪声特性、交流发电机气动噪声预测的不同湍流模型、不同工况下的气动噪声时频特性等。并采用试验研究方法,对交流发电机气动噪声特性进行验证。在此基础上,建立交流发电机气动噪声多目标优化设计模型,对交流发电机进行降噪优化设计。采用不可压缩Navie-Stokes方程、RNGκ-ε湍流模型以及LES湍流模型对车用交流发电机的空气动力学特征进行了三维非定常数值模拟,应用滑移网格技术和FW-H噪声模型对交流发电机进行气动噪声特性研究。通过数值模拟分析验证了交流发电机气动噪声几何模型、数值模型以及所用CFD分析方法的合理性、可行性以及正确性。得到该型交流发电机的气动噪声源为前扇叶和后扇叶,主要影响阶次为6、8、10、12、18等。通过对交流发电机气动噪声的预测,分析12000r/min工况的交流发电机气动噪声流场与声场特性,得到RNGκ-ε湍流模型在交流发电机气动噪声预测方面,其频率在1400Hz以下时,主要阶次及幅值与试验对比吻合较好。同时LES湍流模型在5000Hz频率以下有很好的一致性。针对交流发电机气动噪声特性预测问题,本文通过“去除部件法”对交流发电机有无前、后风扇等进行了相关实验。应用阶次分析原理,研究交流发电机的主要气动噪声特性,得到该型交流发电机的气动噪声主要阶次为6、8、10、12、18等。各主要阶次成分基本来源于冷却风扇噪声。在总噪声的贡献量上,前风扇对12、18阶次贡献比后风扇大,后风扇对6、8、10阶次的贡献较前风扇大,36阶次不是气动噪声的主要影响阶次。通过改变定子线圈绕线方式,得到交流发电机采用定子线圈B绕方式比A绕好,其总噪声声压级和第12、18阶次声压级均降低。通过改变噪声传播途径上的定子线圈孔隙状态,得到12阶次声压级提高1.2dBA,18阶次声压级约降低1.6dBA,对其他阶次影响不明显。考虑交流发电机旋转方向、后风扇挡片高低、前端盖径向栅格倾斜角度以及前扇叶分布角度等四个因素,以低噪声、高流量以及优化频谱结构从而降低单频旋转噪声为多优化目标,对交流发电机气动噪声进行优化设计以及降噪研究。反方向状态的交流发电机总噪声大且流量小；后风扇无挡片的交流发电机总噪声声压级和质量流量均降低；改变前端盖径向栅格倾斜角度以及采用矢量合成方法对前扇叶分布角度优化后,其总噪声声压级降低,质量流量提高。文中所得车用交流发电机气动噪声特性以及降噪方法,可为交流发电机的气动性能和高转速下总噪声的改进提供一种切实可行的参考依据。
[Abstract]:Vehicle alternator is a device for converting mechanical energy into electrical energy through the pulley connected to the engine, with the increase of rotational speed, aerodynamic noise becomes more and more important part of the AC generator noise. It is important to study the alternator aerodynamic noise characteristics and noise reduction method for AC generator. The aerodynamic noise problem the calculation method to establish the AC generator of the aerodynamic noise analysis of main gas radiation of aerodynamic noise source parts of the dynamic noise characteristics of different turbulence models in predicting the aerodynamic noise of AC generator, under different working conditions of the aerodynamic noise. The time-frequency characteristics and research methods of alternator aerodynamic noise characteristics verified. On this basis, the establishment of the alternator aerodynamic design optimization model of multi objective noise reduction, the optimization design of the alternator.
The incompressible Navie-Stokes equation, RNG k-e turbulence model and LES turbulence model for three-dimensional unsteady numerical simulation of the aerodynamic characteristics of vehicle alternator, using sliding grid technology and FW-H noise model of aerodynamic noise characteristics research of AC generator. Analysis to verify the geometric model of aerodynamic noise generator through numerical simulation, the numerical model and the rationality of the CFD analysis method, the feasibility and correctness of the AC generator. The aerodynamic noise source for the front door leaf and after fan, mainly affects the order is 6,8,10,12,18.
The prediction of AC generator of the aerodynamic noise analysis of AC generator gas 12000r/min conditions in the flow field and aerodynamic noise characteristics of sound field, RNG k-e turbulence model in AC generator gas aerodynamic noise prediction, the frequency below 1400Hz, the main order and amplitude with test results agree well. At the same time the LES turbulence model are consistent good at 5000Hz frequency.
According to the features of the noise generator aerodynamic prediction problem, this paper through the removal of parts of the alternator has no law "before, after the fan for the relevant experiments. By applying the principle of order analysis, the noise characteristics of the main gas of the AC generator, the AC generator aerodynamic noise is mainly the order is 6,8,10,12,18 the main components of the order. The basic source of the cooling fan noise. The contribution of the total noise, the fan of 12,18 order contribution than the fan, the fan of 6,8,10 after the order of the 36 big fan contribution than before, the order is not aerodynamic noise mainly affects the order by changing the stator coil. Winding method, obtained by B AC generator stator coil winding around the better than A, the total sound pressure level and the noise of 12,18 Order sound pressure level decreased. The stator coil pore state changes the transmission path of the noise, get 12 order The sound pressure level is improved by 1.2dBA, and the Second Order sound pressure level is reduced by about 1.6dBA, and the influence on other order is not obvious.
Considering the direction of rotation of the alternator, fan baffle height, tilt angle of the radial grid and the front cover before the fan blade angle distribution of four factors, with low noise, high flow rate and optimize the spectrum structure so as to reduce the noise for single frequency rotation optimization target of alternator aerodynamic noise optimization design and noise reduction research. The total noise generator against the direction of state large and small flow; no baffle alternator total sound pressure level and the quality of flow fan decreased; change the front cover angle and the radial grid vector synthesis method of fan blade angle distribution optimization, the total sound pressure level decreased, mass flow rate increased.
The aerodynamic noise characteristics and noise reduction methods of vehicle alternator can provide a practical reference for improving aerodynamic performance and improving total noise at high speed.

【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U463.631;TB535

【参考文献】