郦志俊　朱茂桃　王宽　张鹏飞

摘 要：采用计算流体力学（Computational Fluid Dynamics，CFD）和计算气动声学（Computational Aeroacoustics，CAA）分步耦合方法对汽车前端冷却模块气动噪声进行数值分析。将换热器部件等效为多孔介质，利用大涡模拟（Large Eddy Simulation，LES）捕捉冷却模块声源信息。利用声学边界元法（Acoustic Boundary Element Method，BEM）计算气动噪声，并将计算结果和噪声试验结果进行对比。结果表明，冷却模块空间声场低频段轴向偶极特征明显；离散噪声突出而宽频噪声相对较小；场点总声压级随转速的增大而增加；出风口场点总声压级较进风口大；增加等效声源数量可提高气动噪声的数值预测精度。计算结果与试验结果吻合较好，说明CFD和CAA分步耦合方法可为冷却模块低噪声设计提供理论指导。

关键词：冷却模块；气动噪声；多孔介质；旋转偶极子；声学边界元法

中图分类号：U464.138文献标文献标识码：A文献标DOI：10.3969/j.issn.2095-1469.2015.06.11

Abstract：Numerical analysis of aerodynamic noise was conducted for an automotive front-end cooling module based on a CFD and CAA hybrid method. Heat exchangers behave like an equivalent porous medium. the large eddy simulation （LES） was utilized to obtain the characteristics of the aeroacoustic source. The acoustic boundary element method （BEM） was implemented to compute the aeroacoustic field. Finally， the comparison between predicted and measured values demonstrates that the acoustic response has a strong dipole characteristic at low frequency. Tonal noise is prominent while broadband noise is relatively lower. The total sound pressure levels at measuring points increase with rotational speed. The sound pressure level at outlet is higher than inlet. The prediction accuracy is improved by increasing the number of equivalent acoustic sources. The CFD and CAA hybrid method is applicable to the design of low-noise automotive front-end cooling module.

Key words：cooling module； aerodynamic noise； porous medium； rotating dipole； acoustic boundary element method

汽车前端冷却模块作为汽车热管理系统的重要组成部分，是汽车的主要噪声源之一。随着汽车驾驶员和乘员对声舒适性要求的不断提高及相关汽车噪声标准法规的日趋严格，开发低噪声汽车前端冷却模块具有重要意义。汽车前端冷却模块由中冷器、冷凝器、散热器等换热器部件和冷却风扇模块化集成而成，示意图如图1所示。

气动噪声是汽车前端冷却模块噪声的主要部分，其产生和传播与冷却模块外部复杂流动密切相关。在冷却模块流场分析方面，Puntigam等人[1]对汽车冷却模块流场特性进行数值研究，验证冷却模块流场仿真的可靠性。……