Development of an aero engine life prediction methodology for preliminary design multi-disciplinary optimisation assessments

摘要

A methodology for preliminary aero engine life prediction based on the life estimation of high-pressure turbine blades and discs is presented. It features in Cranfield University's Techno-economic Environmental Risk Assessment (TERA) framework which shall help to realise the complex and challenging requirements on novel propulsion system integration specified in the 2050 Strategic Research & Innovation Agenda (SRIA) goals. The TERA tool is based on detailed and rigorous thermodynamic representations of power plants, integrated with other appropriate models including aircraft performance, engine emissions prediction, weight, dimensions and life prediction. It is capable of rapidly exploring the design space for multi-disciplinary and multi-objective optimisation, such as assessing trade-offs between minimum mission fuel burn and maximum engine life. Since not all engines within a fleet of engines perform equally, for example due to manufacturing tolerances, engine deterioration, and hence life, is assumed to be scattered. The herein proposed methodology describes common engine failure mode calculations based on component stress and temperature in terms of random variables. Thereby it is possible to account for the population of engines within failure mode calculations. The methodology is applied to a typical TERA case for a reference aircraft and engine combination. The influence of different ambient conditions and mission ranges on engine life is under investigation. It was possible to calibrate the design life of the reference engine using the proposed methodology. Furthermore, qualitative trends in engine life were observed.