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-   -   Turbine blades on jets questions (https://www.pprune.org/tech-log/9543-turbine-blades-jets-questions.html)

Anthony2107 15th November 2000 14:42

Turbine blades on jets questions
 
There are two types of turbine blades in the jet engines. One is the "impulse " type turbine,which relies upon the nozzle vanes to convert the combustion gas static pressure to high velocity jets, and are shaped to produce a large deflection of gas resulting in a tangential force by flow direction change.
The other one is the "reaction" type shaped to provide a pressure drop and velocity increase across the blades thereby producing tangential force as well.
But wait a cotton pickin' minute, which one is more efficient though ? ( more work for less fuel )
To the Boeing jocks - Which one does Rolls Royce use ?



Trash Hauler 15th November 2000 15:04

I am not sure which one was claimed to be more efficient.

The third option that you did not mention is the hybrid "impulse/reaction' from my reading most modern engines (RR, P&W, GE etc) utilise turbine blades that have facets of noth principles in their design.

Cheers


Anthony2107 15th November 2000 16:15

TH

I intentionally did not mention the third one because the hybrid are a mix of the two therefore for obvious reasons getting the best of both designs.
I just want to know which of the two are more efficient and if any of these two are used independently in any engines? Esp R.R.



exeng 15th November 2000 16:49

I was taught many years ago as an engineering apprentice that 'Reaction' blades were more efficient. However I believe that modern blades are a combination of both reaction and impulse.


Regards
Exeng

Anthony2107 16th November 2000 09:50

Thanks Exeng - that'll do me.


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