Study of the Nonsteady Flow in a Multipulse Converter

In a previous paper [1] a simplified model has been proposed to calculate the pressure loss coefficients of a multipulse converter under steady-state flow conditions. Therefore a special test rig has been built, which simulates the nonsteady but cyclic flow in the exhaust system of a real engine. Pressure and velocity measurements (with LDA) are compared with the results of the numerical simulation for the flow through the multipulse converter of the test rig. Finally, a comparison is made between measurements and calculations of the pressure history in the exhaust system of a real engine. This paper proves that this simplified model accurately predicts the behavior of the multipulse converter under nonstationary flow conditions.