|Quoting Faro (Thread starter):|
In the same line of thinking, how long can a modern high-bypass turbofan operate before having to change the following:
- the reversers;
- the bypass duct;
- the nozzle;
- the fan;
- the LP & HP compressor stages & stators;
- the combustion chamber; and
- the LP & HP turbine stages & stators.
The reversers and bypass duct, on most planes, are the same part and are on-condition maintenance. In other words, they don't have explicit life limits, you just run them until they die. Normally, that happens due to wear in the non-replaceable moving parts (e.g. slides), then you pull them for overhaul. The structure is essentially infinite life.
The nozzle and fan are usually similar; you do regular inspections and repair as necessary. Nozzles usually succumb to sonic-fatigue cracking eventually, and fans to FOD or wear. However, you usually do fan's on a blade-by-blade basis, so you're unlikely to change an entire fan at once.
Compressors eventually wear out (abrasion) and, depending on the engine, may be life-limited by fatigue or on-condition limited by allowable blade wear. Stators don't fatigue, but do wear.
Combustion chambers and turbine stators undergo thermal cycling fatigue, and ablation/abrasion...they're basically slowing wearing away from the day they were made and eventually hit their life-limits, which is supposed to occur before they fail.
Turbine rotors have all the wear problems of the stators, plus ferocious fatigue problems due to the high loads. As far as I know, they're all life limited by fatigue, if they don't fail due to wear (increasing EGT) first.