整车环境下汽车空调系统气动噪声分析

针对汽车空调(Heating,Ventilation,and Air-Conditioning,HVAC)存在噪声过大导致舒适性较差的问题,通过试验为主、数值仿真为辅的方法对整车环境下空调系统气动噪声进行了研究。研究发现,空调系统产生的气动噪声呈宽频噪声特性。整车环境下空调系统辐射出来的噪声量级比自由场环境高11.7 d B(A),声压级较大的频带更宽,呈现出明显的混响场特征。在空调风机转速为7档、内循环工况时,测点C处的总声压级高达67.9 d B(A),超过企业内部标准要求1.9 d B(A)。风机是主要噪声源,应在后期降噪中加以控制。由于乘员的阻挡和衣物的吸声,乘员舱空间缩小,坐有乘员时相同测点的总声压级小1.5 d B(A),在125 Hz以上各频率段的声压级均有不同程度的降低。文中研究可为明确空调系统在乘员舱的声辐射特性和空调系统噪声控制提供参考。

Analysis of aerodynamic noise from HVAC in the vehicle

Considering the noise generated by automobile heating, ventilation, and air-conditioning (HVAC), the study of the aerodynamic noise in passenger cabin is conducted by means of tests as well as numerical calculation. Results show that the aerodynamic noise induced by HVAC is broadband. The overall sound pressure level (OSPL) in the cabin, where the noise field can be seen as a reverberant field, is 11.7 dB(A) higher than that in free field, and a wider frequency band appears at higher sound pressure level. OSPL at measuring point C is up to 67.9 dB(A) including an excess of 1.9 dB(A) in the recycle mode with a maximal fan speed. As the primary noise source, the fan needs to be concerned in the following research on noise control. Due to the blocking effect of passengers and acoustic absorption of garment, the cabin space is reduced, and correspondingly OSPL shows a decrease of 1.5 dB(A) at the frequency above 125 Hz compared with that in no-passenger condition. This study can provide a reference for understanding the sound propagation in cabin and the noise control of HVAC.