Compressor Sound - Modelling and simulation of flow acoustics of compressors in turbochargers of vehicle engines

An effective technology to reduce emission and fuel-consumption is the use of turbochargers. A turbocharger increases the air pressure at the inlet manifold of the engine by using the waste energy from the exhaust gas to drive a turbine wheel that is linked to the compressor through a shaft. Besides the use in combustion engines, fuel cell systems for vehicle applications also need compressed air to achieve high power densities. Thereby, in fuel cell systems the noise emission of turbochargers is no longer masked by the combustion engine. In operation, the main noise sources are generated by the flow in the compressor and the different noise phenomena need to be understood in order to efficiently reduce the emitted noise and increase comfort. A huge potential in order to achieve this goal is a simulation based investigation to study in detail the flow mechanism, the aeroacoustic sources and its sound propagation. The main goal of this research project is to develop a physical model and based on it an enhanced simulation environment, which is capable to compute the source mechanism in compressors and the sound propagation in the whole turbocharger.