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Igntion system suggestions/considerations

  1. May 16, 2013 #1
    Hi,

    We are building a turbojet engine / gas turbine engine for our graduation project.

    We were looking out for ignition system for the combustion chamber.
    The fuel is LPG (20% propane 80% butane)

    What can be the best way to ignite a spark to light the flame in the combustion chamber to start the engine?



    We think that a lighter will not work because it has very little ignition energy.
    And we also think that holding a flame from a source such as matchstick or any other source cannot work, since airflow will extinguish the flame before combustion gets self sustaining in the combustion chamber.



    Suggestions?
    Is there a simple way to use spark plug?
     
  2. jcsd
  3. May 16, 2013 #2

    SteamKing

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    This guy used a lighter on his homemade turbine:



    It may not be the safest method, but it was effective. If you want some extra distance, you could probably use a fireplace lighter.
     
    Last edited by a moderator: Sep 25, 2014
  4. May 16, 2013 #3
    Or a bunson burner or similar device (you've already got the LPG).
     
  5. May 16, 2013 #4

    AlephZero

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    Compared with standing that close to a home-built engine with a high speed rotor and no obvious containment system for broken bits, the safety hazards of lighting it are fairly minor IMO.

    Personallly I wouldn't want to be even in the same room as the engine, for the first test run.
     
  6. May 16, 2013 #5

    SteamKing

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    That's why I suggested a fireplace lighter. However, a long stick with a fire on the end could work in a pinch.
     
  7. May 16, 2013 #6

    Danger

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    Why not just a normal automotive ignition system? If your air/fuel mixture is correct, it'll go.
     
  8. May 16, 2013 #7

    SteamKing

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    I think these guys would like to use what is simplest, like striking a match. Once you get the turbine going, you don't need any more sparks.
     
  9. May 17, 2013 #8
    The thing is we are using automobile turbocharger to build our jet engine.

    So for start up, we will inject fuel (LPG) and at the same time we will spin the blades/shaft using compressed air.

    So the engine is up on airpower, and then we need to ignite this injected LPG to start the engine and make it self sustained.

    If we hold a match, and if we blow air whilst injecting fuel, the air will extinguish the match before LPG starts burning - the combustor design is such that air flow is required in the combustor to make combustion flame self sustainable.


    A spark plug is a good idea, but we found out that we need lots of other components than the battery itself. We need a highly complicated circuit. Another source suggested we need a DELCO, coil and a spinning source to get sparks.
     
    Last edited: May 17, 2013
  10. May 17, 2013 #9
    I suppose you would need a lot of other parts if you really want this to look nice, but if you're just concerned with lighting it up, you can probably take the coil from an automotive ignition system and rig a switch and a wire to it. Just run to the local automotive junkyard and rob the distributor, coil, and a spark plug wire from an older car and you should be set. Might have to tinker with it a bit, but it should work.
     
  11. May 17, 2013 #10

    berkeman

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    Maybe look at using an electronic ignition out of an outdoor gas barbeque. You can probably buy a replacement from a BBQ store or hardware store. That way you can be away from the engine when you fire it up (I agree with AlephZero's cautionary statements...).
     
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