Munjal, M. and Krishna, V., "Flow - Acoustic Performance of a Three - Pass Double - Reversal Muffler," SAE Technical Paper 2013-26-0106, 2013, doi:10.4271/2013-26-0106.
The three-pass double reversal muffler consists of three perforated pipes arranged along the major axis of an elliptical shell with two short end-inlet/outlet chambers at the two ends. Transfer matrices for the three constituents chambers have been combined appropriately in order to the predict the overall transfer matrix and thence Transmission Loss (TL) as well as Insertion Loss (IL) of the muffler. In this paper, a flow-resistance network approach has been presented that makes use of the electrical circuit analogy in order to evaluate the mean flow distribution, which is then extended to evaluate the overall back pressure of the muffler. It is shown that the proposed muffler configuration has strikingly low back pressure-less than one dynamic head.