Modeling and Simulation of a Supercharger

Abstract

A dynamic model is developed for simulating and predicting performance for superchargers of relatively arbitrary geometric configuration. A thermodynamic control volume approach and bond graph models are used to derive continuity and energy equations linking the various control volumes. Bond graphs also serve to study and understand the causal implications of laws governing flows between control volumes and system dynamics. Heat transfer is neglected. Simulation outputs include time histories of pressure, temperature, mass, and energy associated with each control volume, time histories of the various flows in the supercharger, and overall volumetric efficiency. Volumetric efficiencies are predicted over a wide range of speed/pressure ratio combinations and are within three percent of experimentally measured values. The simulation is used to investigate the sensitivity of supercharger performance to several key design parameters, including rotor-rotor separation, and rotor-housing and side plate clearance distances.