Abstract
One of the techniques to reduce fuel consumption of automotive engines is downsizing. This technique leads to a great increase of the boost level, which corresponds to increase in the power recovered by the turbine. However, the turbine is driven by exhaust gases from the engine which are, by nature, highly compressible and unsteady. This has made critical, the understanding and prediction of the influence of unsteady phenomena on the turbocharger turbine's behavior. This paper deals with the comparison between experimental and numerical results of pressure waves influence on the turbine’s behaviour. Regarding the part dedicated to 1D numerical calculation, two different turbine models were used: a literature one and a laboratory one. Finally, a new model suitable to modelise variable and fixed geometry turbines, in zero or one-dimensional fluid dynamics codes has been developed. It was conclude that this model is able to reproduce with good accuracy the fluiddynamic behaviour of the turbine operating under unsteady flow conditions by using the maps supplied by the manufacturer as the only input data.
Keywords: Turbochargers, Radial Turbine, Unsteady Flow, 1D Modelling, Compressible Flow