Abstract: This paper addresses the low-frequency booming noise issue complained by customers during the mass-production development phase of an automotive air conditioning project. A combined approach of experimental verification and simulation analysis was adopted to investigate the mechanism of this problem. First, experimental analysis is conducted to rule out the structural vibration of the heating, ventilation and air conditioning unit itself and the vibration transmitted along the transfer paths as the primary sources of the vehicle's low-frequency booming noise, thereby narrowing down the issue to the aerodynamic noise inside the heating, ventilation and air conditioning unit. Subsequently, simulation analysis is employed to identify the main noise sources as the backflow and vortex near the volute tongue at the volute outlet side. Accordingly, the system impedance is optimized to improve the fan operating point, and a rectification device is added to reduce backflow and vortex. Finally, the optimization scheme is verified through experimental tests, and the results demonstrated that the scheme significantly mitigated the low-frequency booming noise. The methods described in this paper can provide a reference for the optimization of noise issues in automotive air conditioning systems.

Key words: automotive air conditioning; low-frequency noise; simulation analysis; experimental verification

摘要： 文章针对某汽车空调项目在量产开发阶段客户抱怨的低频轰鸣声问题，采用试验验证 与仿真分析相结合的方法，对该问题的产生机理进行研究。首先，通过试验分析排除空调箱 本体结构振动及传递路径振动为整车低频轰鸣声的主要噪声源，将问题锁定为空调箱内部气 动噪声。其次，借助模拟仿真分析，推定噪声源主要为蜗壳出口侧靠近蜗舌附近的回流与涡 流，进而通过优化系统阻抗改善风机工作点，并增加整流装置以降低回流和涡流。最后，对 优化方案进行试验验证，结果表明该方案显著改善了低频轰鸣声问题。文章所述方法可为汽 车空调噪声问题的优化提供参考。

关键词: 汽车空调；低频噪声；仿真分析；试验验证