Propulsion System Integration and Optimization at the Preliminary Design Phase

Abstract

Abstract: The turbine design of an aero-engine is a multidisciplinary iterative process that involves not only the designing of several components (disc, coverplate, fixing, platform, airfoil, shroud segments, turbine support case, etc.) but also the synergy of multiple disciplines and the application of all their knowledge to create the ideal set of components for the design conditions. Traditionally, the design of these components has been separated into the pre-detailed and the detailed design phases. Unfortunately during the preliminary stage of the design, engineers are not given enough time to achieve a balance between the fidelity of the results and the time taken to achieve them. This may lead to costly redesign as it is extremely difficult to correct an unsatisfactory concept at a detailed design phase of an engine. The use of Multidisciplinary Design Optimization techniques at a preliminary design phase (Preliminary MDO or PMDO) allows correcting this.A design system was created that integrates the design of the turbine based on the thermal and mechanical stresses, aerodynamics and the cooling requirements. This was part of an eventual total Propulsion System Integration and Optimization (PSIO) system. Through leveraging of commercial software such as CAD and CAE, parametric models were created for each turbine component and analyzed. This system allows more knowledge to be injected into the early stages of the design process as it helps to rapidly synthesize a turbine and evaluate its attributes over a wide range of alternative designs at a much higher degree of fidelity than was previously possible at the pre-detailed stage. This system also decreases the risk of human errors as it requires less manual inputs than previous pre-detailed processes. This risk is further reduced by the automation of data transfer between the disciplines that would usually be coordinated manually. This automation does not negate the need of engineering judgment but rather more effectively uses an engineer’s time by letting him focus only on value added decisions. Finally, the simplifications of the procedures that accompany such a system enable one engineer to be able to design a whole turbine from its components geometric design to the analyses’ results post-processing.