Recent content by Jeremy Ardley

  1. J

    Power required to compress air in a gas turbine

    This is a practical example of what I was asking about. Regrettably I don't speak Russian but I get the impression the engine gave '3kg' thrust or around 30 Newtons
  2. J

    Power required to compress air in a gas turbine

    You can see this in high bypass engines - essentially a ducted fan driven by a jet core. A significant portion of the inlet air is driven by the fan, bypasses the jet core, and is later joined with the jet core exhaust (and potentially gets extra energy from the core heat). I think my best bet...
  3. J

    Power required to compress air in a gas turbine

    No. I'm proposing switching it in and out depending on need. For takeoff it's switched in. For cruise it's switched out and thrust is by electric fan only.
  4. J

    Power required to compress air in a gas turbine

    @russ_watters - My error. Pcombust = 3 x Pin The power output from an electric powered compressor with combustion will be Pin + Pcombust = 4 x Pin. @CWatters A ducted fan is a high(er) bypass engine. At most it will use the Electric Pin. This topic is about boosting the energy of the system...
  5. J

    Power required to compress air in a gas turbine

    @russ_watters No I'm not doing away with the compressor. It will still stay there - probably a radial compressor, though I'm looking at a design right now that uses an electric motor driving an axial compressor https://hackaday.io/project/21569-3d-printed-axial-compressor The idea is that...
  6. J

    Power required to compress air in a gas turbine

    Thanks for the helpful comments. The comment from @CWatters on the power ratios is most useful. Roughly one third of the energy in the combustion chamber is used to drive the compressor and the remaining 2/3 to provide thrust. If all things were equal - and they never are - then an electric...
  7. J

    Power required to compress air in a gas turbine

    The turbine only extracts a fraction of the hot gas energy - essentially by slowing it down. This is used to power the compressor. The thrust of a gas turbine is created by the mass flow of hot gas out of the rear nozzle. In optimum designs this is at local atmospheric pressure but with high...
  8. J

    Power required to compress air in a gas turbine

    I'm looking for advice on how much power is required to compress air in a gas turbine engine - parameterised by degree of compression and mass flow. Normal gas turbine engines have exhaust turbine(s) on the same shaft as the air compressors. They bleed some of the exhaust energy to drive the...
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