基于声学有限元的柴油机增压器压气机气动噪声研究

为研究船用低速柴油机增压器压气机气动噪声,采用计算流体动力学和声学有限元的混合计算方法进行了数值预测。通过试验对压气机计算模型进行了验证。在3个工况下对压气机非定常流场进行了计算,其中压力脉动被用作声学计算中的声源信息;采用声学有限元方法对压气机气动噪声进行了预测。结果表明:计算流体力学和声学有限元的混合计算方法具有较高的计算精度,可以用于压气机气动噪声数值预测;压气机进口气动噪声主要谱成分为离散单音噪声和宽频噪声;离散单音噪声在叶片通过频率处有明显的指向性,存在两个突出峰值。

Study of Aerodynamic Noise of a Diesel Turbocharger Compressor Based on Acoustic Finite Element Method

A hybrid numerical method that composed of computational fluid dynamics (CFD) and acoustic finite element method (FEM) was employed in this research, in order to study the compressor aerodynamic noise in a marine diesel engine turbocharger. The numerical model was validated against with experimental data. The compressor unsteady flow was calculated under three different working conditions, the pressure fluctuation was used as noise source in acoustic simulation. Then, compressor aerodynamic noise was pre-dicted using FEM. The results indicate that the hybrid method that combined with CFD and FEM has enough accuracy, which means that the method can be used for predicting compressor aerodynamic noise. The main components of compressor aerodynamic noise include discrete tonal noise and broadband noise. The tonal noise exhibits obvious acoustic directivity at blade passing frequency (BPF), there are two peaks at compressor inlet area.