Radial turbine geometrical parameters optimization based on CFD analysis and application to engine performance assessment

The current trend of vehicle manufacturers is increasingly driven towards the use of downsizing technology, which coupled with turbocharging technique, allows obtaining engines with higher power densities and characteristics in terms of emissions, performance and fuel consumption much better than a conventional engine. The achievement of this target is clearly not any easy task for developers which have to perform a considerable amount of studies to optimize the system and find the compromise which best fits all requirements. Therefore, fluid dynamic analysis, using dedicated CFD software, in addition to experimental tests, are fundamental for the analysis and optimization of engine turbomatching: the former in particular becomes essential considering the lack of data often available and the huge amount of time required at the test bench. The objective of the thesis was to develop a methodology that could be used for radial turbine geometrical parameters optimization based on CFD analysis and its application to engine performance assessment. Initially, 3D fluid dynamic studies will be performed on the model, in order to evaluate the actual behaviour of the component, in terms of pressure and temperature drop and gather useful data. Afterwards, collected information will be used to simulate the response of the system using the overall model of the engine created through GT-Power in a 0-dimensional approach, firstly evaluating the standard turbine and then rating the impact that geometry changes on turbine design could have on overall engine performance.