Implications of engine deterioration for a high-pressure turbine-blade's low-cycle fatigue (LCF) life-consumption

As a result of experiencing a deterioration of efficiency and/or mass flow, an aero-engine will automatically adjust to a different set of operating c haracteristics; frequently resulting in changes of rpm and/or turbine entry -temperature in order to provide the same thrust. As such, the stresses tha t the engine is subjected to will change land thereby alter the blade's low -cycle fatigue-life consumption) relative to that for an engine suffering n o deterioration (i.e. in the jargon-a 'clean' engine). Rises in the turbine 's entry-temperatures and the high-pressure turbine's rotational-speed resu lt in greater rates of creep and fatigue damage being incurred by the hot-e nd components and thereby higher engine's life-cycle costs. Possessing a be tter knowledge of the effects of engine deterioration upon the aircraft's p erformance, as well as fuel and life usages, helps the users to take wiser management decisions and hence achieve improved engine utilization. For a m ilitary aircraft, by employing a bespoke computer simulation, the consequen ces of engine deterioration on a high-pressure turbine blade's low-cycle fa tigue-life consumption are predicted. (C) 1999 Elsevier Science Ltd. All ri ghts reserved.