Analysis of Intake Silencer Insertion Loss in a Marine Diesel Engine Turbocharger Based on Computational Fluid Dynamics and Acoustic Finite Element Method

The analysis of intake silencer insertion loss (IL) was conducted using a hybrid numerical method, which combined computational fluid dynamics (CFD) and acoustic finite element method (FEM). First, an experimental test was conducted to obtain the compressor intake noise spectrum under two different conditions: the turbocharger directly connected to the substitution duct and to the intake silencer, respectively. Then, the hybrid numerical method was introduced to predict the intake noise propagation. The compressor unsteady flow was calculated under the two different conditions, the pressure fluctuation on the impeller inlet plane was then extracted as noise source. The noise propagation under two different conditions were obtained. The comparison of numerical and experimental results indicates that the hybrid method used in this paper can predict the IL in different conditions as the IL under three different compressor working conditions was consistent with the experimental values. Furthermore, the noise spectral characteristics and acoustic directivity of compressor intake noise were also discussed.