Analysis and design guidelines for fork muffler with H-connection

Abstract

The Herschel-Quincke (H-Q) tube phenomenon has been applied to favorably alter the performance of the Fork muffler (or dual muffler) by interconnecting the two halves of the fork muffler system by means of a tube (H-connection). Although there is only one additional tube in the inter-connected fork muffler (fork muffler with H-connection), yet it substantially changes the acoustic impedance felt at the source. In order to understand the effect of the H-connection, we need to carry out the analysis of the whole exhaust system. This paper first deals with the analysis of the fork muffler (which falls under the category of single-inlet multiple-outlet muffler) with and without H-connection using the transfer matrix approach, the results of which have been validated by a means of a 3-D finite element analysis. In general, the convective effect of the mean flow plays very little role in the performance of the muffler. But, the mean flow effect at the H-junctions may be crucial to the effectiveness of H-connection and its effect has been taken into account in the parametric study of the fork muffler with H-connection. The dissipative effect of the mean flow at the perforations has been considered throughout the analysis. The parametric study of the fork muffler with H-connection is then carried out to construct the design guidelines for efficient use of the H-connection in designing exhaust systems.