Learning About Air Coupling in Shafts - Diagrams Welcome!

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Discussion Overview

The discussion centers around the concept of air coupling in shafts, specifically exploring how such systems operate and seeking diagrams for better understanding. Participants are attempting to clarify the mechanics and applications of air coupling, particularly in relation to turbine engines.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant expresses difficulty in finding information about air coupling between shafts and requests diagrams.
  • Another participant questions the existence of air coupling for shafts and asks for examples of applications.
  • A participant suggests a potential connection to concentric counter-rotating shafts.
  • One participant compares air coupling to the interaction between two fans, suggesting it may be a weak form of coupling, possibly more effective in viscous fluids.
  • A participant mentions reading about air coupling in the context of turbine engines from Pratt & Whitney but cannot locate the reference.
  • Another participant likens air coupling to a hydrostatic drive but questions its efficiency.
  • A participant explains that axial flow from one fan can impart energy to another fan's blades, leading to rotation, and discusses conventional turbo-compressors and turbines involving stationary and rotating blades.
  • One participant notes that engine spools can counter-rotate and mentions the use of curvic couplings in mechanical applications, expressing interest in further research on the topic.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the nature or effectiveness of air coupling in shafts, with multiple competing views and uncertainties expressed throughout the discussion.

Contextual Notes

There are limitations in the discussion regarding the definitions of air coupling and its applications, as well as the efficiency of the proposed systems. Some participants reference specific applications without providing detailed explanations or links.

Who May Find This Useful

This discussion may be of interest to individuals exploring mechanical engineering concepts, particularly those related to coupling mechanisms in turbine engines and fluid dynamics.

Shawnzyoo
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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?
thanks
 
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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?
 
Does this have anything to do with concentric counter-rotating shafts?
 
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
 
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
 
So it's like a hydrostatic drive without the hydro? Sounds pretty inefficient.
 
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?
 
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.
 
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