On the Development and Application of Accurate Numerical Models for the Computation of Steady and Unsteady Flowfields in Turbomachinery

The present thesis deals with aspects of the very complex field of steady and unsteady computational fluid dynamics (CFO) on turbomachinery applications, and has been performed by the author at the turbomachinery laboratory of the ETH Zurich (LSMIETHZ) and at ALSTOM Switzerland Ltd. since 2002.The contents of this work can be separated into two main parts, one is the development and validation of the numerical method and the other is the application of the method on several unsteady problems in turbomachinery to investigate unsteady loss production. In this respect the methods have been applied for a detailed investigation in steady and unsteady loss production in axial turbines with special respect to effects of unsteady trailing edge flow, variation of Reynolds number, blade scaling, axial gaps between stators and rotors, aspect ratio and rotor tip leakage.