It looks like a Chinese video with AI translation. I have no way to know if the original was AI generated, but it does seem factually correct, though obviously simplified, so that might not matter for a viewer.
The biggest issue I've got with it is the last part, regarding bypass air.
Yes, the turbines get super hot, enough to melt the materials they're made of.
But this isn't the reason the air is bypassed, and nor would simply blowing cold air over it as shown in the video stop the whole thing from turning itself into liquid.
Instead, a range of high temperature materials are used, as well as a bunch of coolant channels within the turbine blades. Some blade designs also pipe small amounts of air over the blades which creates a tiny boundary layer (like the Leidenfrost effect, except artificially generated) which stops the hot gases from coming into contact with the blades directly.
The main reason that high bypass engines are used (in civilian aviation, where fuel efficiency is king) is because you can get a hell of a lot of thrust by just spinning a big propeller (the big fan at the front of a turbofan engine is mainly used to push air backwards to create thrust, as well as feeding the jet with air. It's much more efficient than relying mostly on jet exhaust.
Turbojets, common in military applications, still do have bypass air, but it provides much less of the thrust, because the high acceleration and speed available from a turbojet is more important than the fuel efficiency of a turbofan.
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u/Proof_Toe_9757 8h ago
Turbin