Utilization of a Twin Scroll Radial Centripetal Turbine Model 2019-01-0191

The paper deals with the utilization of the map-less approach in simulation of a single and twin scroll radial turbine. The conventional steady flow maps are not used. An unsteady 1-D model of a twin scroll turbine includes scrolls, mixing of flows upstream of the impeller, turbine wheel, leakages and outlet pipe. Developed physical turbine model was calibrated by experiments at specific steady flow turbocharger test bed with open loop, which enables to achieve arbitrary level of the impeller admission via throttling in separated sections. A selected twin scroll turbine was tested under full, partial and extreme partial admission with closed section. The required number of operating points is relatively low compared with the conventional steady flow maps, when the maps have to be generated for each level of the impeller admission. The calibration process of the full 1-D turbine model is described in detail. The fully calibrated 1-D twin scroll turbine model in conjunction with the internal combustion engine model is able to describe processes inside a turbocharger turbine under highly pulsating flow. The experiments were also performed on a turbocharged six cylinder diesel engine with twin scroll turbine. The engine was tested at steady and transient load and speed operation. The model of the internal combustion engine with full 1-D model of a twin scroll turbine was properly calibrated by obtained experimental data. The simulation results of steady states and transients were compared with experiments. The results of steady and unsteady operation of the turbine and future utilization of the developed simulation tools are discussed.