Quote:
Originally Posted by cRiPpLe_rOoStEr
I was considering something similar to the generator fitted to jet-powered aircraft, coupled to the high-pressure shaft by gears. In a turbocharger, that could be coupled to the shaft at the intermediary section.
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ok ok
thing 1, APU are usually centrifugal gas turbines, turbos are a drive mechanism to compress air fuel mix. In some ways quite similar yes, the same no.
APU do use large gear reductions but they are blessed with usually larger diameter Centrifugal compressors, which turn slower than even higher RPM ridiculous speed turbos. Key point, diameter matters.
Numerous problems circulating around heat. Back to basics, it isnt usual for energy to come for free, therefore expect some pitfalls dependent on your expectations of energy supply.
Not sure if turbo manufacturers are that into airbearings but they should be, because slight deviations due to bearing wear will kill your power generation. Which as I understand turbos bearing wear is exceptionally high, due to massive high RPM. They probably arent because unlike larger compressors they dont have the gas flow to spare, again its that diameter thing.
Heat in circuitry reduces efficiency markedly. Anything you do on that same shaft will transmit heat, and the heat in this case is extreme. There are technologies which could help, like magnetic drives which will separate the physical connection, which will help. Likewise water injection will help. Still, those things glow cherry red when on song, I dont fancy the chances.
Dont like to kill the idea, just trying to illustrate how difficult this task will be. On the other hand if it could be made to work, it has numerous worthwhile applications.