Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Air Coupling

  1. Oct 6, 2005 #1
    I am trying to learn more about air coupling.
    That is the coupling between 2 shafts
    I am having a hard time finding any information on the subject matter
    does anyone know how these systems work and have any diagrams?
  2. jcsd
  3. Oct 7, 2005 #2


    User Avatar
    Science Advisor

    Maybe it's because I haven't had my coffee yet this morning, but I can't say I have ever seen or heard of an air coupling for shafts. Can you point me to an existing application?
  4. Oct 7, 2005 #3


    User Avatar
    Staff Emeritus
    Science Advisor

    Does this have anything to do with concentric counter-rotating shafts?
  5. Oct 7, 2005 #4


    User Avatar
    Homework Helper

    Something like how when you blow one fan into another fan, the second fan's rotors start moving as well? It seems like a very weak sort of coupling... maybe better in more viscous fluids or the other way around? o_O
  6. Oct 7, 2005 #5
    i was reading about this coupling with turbine engines from Pratt & Whitney.
    i can't for the life of me find the link right now

    but i think mezarashi has described it
  7. Oct 7, 2005 #6


    User Avatar
    Gold Member

    So it's like a hydrostatic drive without the hydro? Sounds pretty inefficient.
  8. Oct 7, 2005 #7


    User Avatar
    Staff Emeritus
    Science Advisor

    Certainly, if one takes an axial flow from one fan and impose it on another fan, the second fan's blade will experience energy/momentum from the flow and start to rotate. That would be expected.

    In conventional turbo-compressors and turbines, one normally has a set of stationary blades (stator) and rotating set of blades (rotor). For a very simple turbine or compressor with two stages, one could have counter-rotating blade sets. One can get comparable energy transfer but at reduced rotational speed.

    As for hydraulic coupling - automatic transmissions use just that.

    In the case of PW, how are the turbine engines suppose to be coupled?
  9. Oct 7, 2005 #8


    User Avatar
    Science Advisor

    Engine spools do, at times, counter rotate to the other. The rotational directions are set up via gas path angles in the rotors themselves. I have not really heard of this as a coupling. The usual mechanical coupling is a curvic coupling. I'll do some seariching around now that you gave a hint to it's application. It would be nice to see the link you are referring to.
    Last edited: Oct 7, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Air Coupling
  1. Multiple couples (Replies: 1)

  2. Universal Coupling (Replies: 1)

  3. Shaft couplings (Replies: 2)

  4. Air heater (Replies: 3)