Performance Prediction and Early Design Code for Axial Turbines and its Application in Research and Predesign

This paper presents DLR’s in-house Performance prediction and Early Design Code for axial Turbines PrEDiCT. It is capable of designing multi-stage, multi-spool air-breathing turbines with consideration of coolant flows and different loading levels, relevant for energy, aircraft and general turbomachinery. After pointing out the integration of PrEDiCT into the DLR predesign process and the role of each method involved, its iterative main calculation routine will be presented as well as its thermodynamic and geometrical methods to output a complete turbine annulus with preliminary blades, fulfilling power requirements and coming from a minimal input parameter set. An important aspect is the developed concept for user-driven design work with PrEDiCT involving an interactive GUI and a built-in execution mode called ‘ReDesign’ that retains the design code nature of the program with geometry output, but still allows for effective evolution and tailoring of the global design down to each stage and blade row. The paper closes with the validation and results section, which highlights three examples where the code is applied to axial turbine predesign and research. The intention of this paper is to encourage the use of early predesign methods even by non-OEM organizations, since the presented work has shown for DLR multiple benefits in terms of research work, cooperation with other departments and OEM industry as well as training of personnel. Furthermore the implementation of PrEDiCT facilitated the transition from pre- to detailed design (i.e. 3D CFD) to such an extent, that the still important role of 2D throughflow methods could be questioned, i.e. being less relevant in the future for some design tasks.