空调室内机贯流风扇流动噪音的仿真研究

Numerical Analysis on the Flow Noise in the Indoor Unit and Cross Flow Fan of Air-conditioners

空调室内机空气流动噪音是影响室内舒适性的重要因素,为此对室内机贯流风扇的非定常流场及噪音特性进行了数值分析。采用非均匀滑移网格和RNG k-ε湍流模型对不可压缩流体非定常流动的Navier-Stokes方程进行求解,并采用Ffowcs-Williams and Hawkings模型对空气流场和噪音进行关联,对空调室内机内空气非定常流场及流动噪音进行数值分析,并与实验结果进行比较。结果表明,采用此方法对计算的流动噪音的声音品质和声谱特性都与测量结果有较好的吻合,为空调器空气流场的优化设计和降低空调器风扇及空气流动噪音的研究提供了有效工具。

Air flow noise is an important parameter influencing the amenity of indoor environment, which is mainly caused by the cross flow fan in the indoor unit of air conditioners. The noise prediction method is presented by integrating the unsteady flow field simulation and aerodynamic noise model. The unsteady incompressible Navier-Stokes equation is solved with RNG k-ε turbulence model with a sliding mesh technique. The aeroacoustic pressure is calculated by Ffowcs-Williams and Hawkings equation. The unsteady pressure data, which is calculated from the unsteady flow field, is used as input data for the FWH equation. This method is applied to analyze the unsteady flow field and flow noise of the cross flow fan in the indoor unit, and the predicted sound pressure level and acoustic spectrum agree well with the measured data not only total noise but also broadband noise. These results show that this numerical method can be used as an effective tool for optimization of axial fans for compact design, large air volume and low noise.