Estimation of temperature drop in exhaust systems

Abstract

The analysis of the acoustic performance of exhaust systems is affected by the flow speed and temperature of the exhaust gases. The flow speed affects the convective wave speed and changes the acoustic properties of some acoustic elements such as perforates. The temperature of the exhaust gas affects its density and the speed of sound. It is important to model the flow and temperature distribution within the exhaust system in order to perform an accurate acoustic simulation. The acoustic propagation along an exhaust system can be modeled by dividing the exhaust system into a number of two-port elements. It has been previously shown that flow distribution and pressure drop calculation can be done using the same two-port elements but using a different set of transfer matrices. In this paper, we are proposing a new method to calculate the temperature drop using the same two-port elements but using another set of transfer matrices. This technique has the advantage to solve all physics by defining only one network. The heat is dissipated through the pipe wall via convection, conduction, and radiation. Several cases were designed to validate the new technique. They show that it works as expected.