Corrected one-dimensional approach for the acoustic simulation of expansion chamber silencer

The error in acoustic performance calculation of silencers with the traditional one-dimensional (ID) approach increases with the growing of frequency, thus, the end corrected coefficient of duct was used to improve the accuracy of the ID result in present paper. The two-dimensional axisymmetric analytical approach was developed to calculate the end correction coefficient and the effect of geometry factor and frequency on the end correction coefficient was studied. The end correction coefficient decreases with the increase of radii ratio and grows with the increase of frequency. The end correction coefficient is invalid for the frequency above the cut-off frequency. Based on the results, a fitting expression was obtained for the end correction coefficient and then employed to correct traditional ID approach. Using the corrected ID approach, transmission loss of expansion silencer was calculated and compared with experimental measurement and finite element method (FEM) result. The comparisons showed that the results accuracy of corrected ID approach was improved greatly.