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Thread OP
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Discussion
What's all this stuff about Efflux?
I thought there might be interest in this topic, evidently, I was wrong. I requested the moderator close this thread before it wasted any more of our time.
Ron |
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Last edited by Ron Pogue; Oct 26, 2008 at 11:42 PM.
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Uh oh.....
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Thread OP
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Hi Turbonut -
This is not about a war, or somebody is smarter than somebody else. I firmly believe that mature individuals can discuss physics in a calm give and take manner, as long as they leave their own personal issues out of it. If it gets stupid, it can be closed. What do you think? Ron |
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Quote:
The term "efflux" is used to describe in our case a fluid exiting the fan or duct. The balloon does describe in a simple way how a rocket works. Pressure is built up in a chamber from burning fuel in the rockets case with a by product of gasses(mass flow) exiting the combustion chamber producing thrust(efflux). The fans we use have no pressure component as air flow leaving the rotor are exiting an open hole(bare fan) or the outlet of the exhaust duct which might be less area than the FSA in which case the flow will accelerate so that the same mass that entered the fan will exit the fan since we are not combusting any fuel. So the balloon example only tells a part of the story. In fact the whole story dealing with efflux and maximizing it against using a simple 100% FSA outlet is efflux boosts the thrust that will be acting on the aircraft at speed. Example: the aircraft makes 10lbs drag at 150mph and 12lbs at 160mph, if we have a thrust force of 12lbs and an efflux of 170mph @85%FSA then at 150 we would see 1.5 lbs extra thrust showing that the we would have some power left for acceleration. At 160mph we would see .7lbs extra thrust but the forces are in equilibrium and no more acceleration will occur so the outlet is not optimal for the example. Now if we were to have just a 100% FSA our speed would be limited to the Efflux velocity because if we cant force the air to go faster than the speed of the aircraft we wont have any accelleration. This is were the outlet becomes important, it will add load but it will add velocity to the flow. Eric B. |
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Last edited by AirX; Oct 26, 2008 at 07:43 PM.
Reason: Added Comment
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Quote:
Thank you |
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