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Title: A study of mixed flow turbine blade geometry for automotive turbochargers
Author: Leonard, Thomas
ISNI:       0000 0004 6061 6931
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2016
Availability of Full Text:
Full text unavailable from EThOS. Thesis embargoed until 01 Nov 2021
Turbocharging a downsized automotive engine presents a number of challenges, requiring high efficiency across a wide range of operating conditions as well as good transient performance in moving between these conditions. For the turbine stage, this requires a high efficiency off-design conditions and a low rotating inertia for the wheel. The use of a mixed flow turbine wheel can be advantageous for both of these requirements. A detailed numerical and experimental study was completed, considering both mechanical and aerodynamic performance, on a range of mixed flow turbine geometries. The performance of these designs was benchmarked against an existing, state-of-the-art radial turbine wheel. The benefit of the designs for the transient performance of a downsized automotive engine was also judged based on published data for trade-offs between inertia and efficiency, established from engine simulations. The results showed that a mixed flow turbine could achieve improved off-design performance and a lower inertia than the baseline radial rotor. It was found that it was possible to vary the inlet blade geometry to achieve a reduction in rotor inertia and to increase the efficiency of the rotor at the off-design conditions, which would greatly benefit the transient performance of the turbine stage. The geometry of the turbine outlet was also varied, and it was found that adding material towards the hub of the rotor, at low a radius, significantly improved the mechanical performance of the rotor, for a small increase in rotor inertia. A study of the hub and shroud contour of the turbine also showed that improved off design efficiency could be achieved with a shallower hub curvature, but that this was also accompanied by a large increase in rotor inertia.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available