Simulation of Sound Transmission through Automotive Turbochargers

The use of turbochargers for production cars has been increasing due to the current trend of engine downsizing. Acoustically, it acts as a damper of the pressure pulsations from the engine that propagate through the intake and exhaust system. This effect is referred to as the passive acoustic properties of a turbocharger. The aim of this paper is to investigate the passive acoustic properties of an automotive turbocharger compressor and turbine and to develop and verify an acoustical model of the turbocharger.

To investigate the acoustic properties such as the transmission loss and the transfer function through these elements under different operating conditions, acoustic two-port measurements were performed on a turbocharger test rig at different flow conditions. A geometry-based acoustical model of the turbocharger was developed for both the compressor and turbine to provide both the transmission loss and the transfer function of these elements and verified by means of non-linear time-domain 1-D gas dynamics simulation.

A good agreement between measurement and simulation of the upstream and downstream acoustic transmission loss of the turbocharger was achieved and it also illustrates an improvement of simulation quality using the new models.