The paper presents a fluid dynamic model of fixed and variable geometry turbines. The aim of this model is to provide an efficient boundary condition to model turbocharged internal combustion engines with one-dimensional gas dynamic codes.
The model is based on the measured characteristics of the turbine from its very conception. Nevertheless, it is capable of extrapolating operating conditions which differ from those included in the turbine maps, since the engines usually work within these zones.
The presented model has been implemented in a one-dimensional gas dynamic code and has been used to calculate unsteady operating conditions for several turbines. The results obtained have been compared with on-engine measurements of instantaneous pressure evolutions upstream and downstream of the turbine.