Development and Experimental Validation of a Low Order Turbine Model Under Highly Pulsating Flow

The flow through radial turbines in automotive turbocharging applications is inherently highly unsteady, exhibiting high amplitude pulsations of varying frequencies. This can have a significant effect on the performance of the turbine, and therefore accurate modelling of these effects is key in good engine design, particularly in the realm of 1-D modelling. Assuming that the turbine stage acts in a quasi-steady manner can result in modelling errors. To better capture the physical effects of unsteady flow, a novel 1-D model of a radial turbine volute was developed, within the engine modelling software GT-Power. A meanline model was developed and integrated into the volute model as a means of modelling the rotor, which was assumed to be quasi steady. Experimental work was done to characterise the unsteady performance of the turbine, and the results were used to validate the model. The model showed good agreement with experimental data as well as some small improvements compared to industry standard methods of modelling.