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Old 20th Apr 2013, 15:26
  #144 (permalink)  
goarnaut
 
Join Date: Nov 2012
Location: Europe
Posts: 15
Thrust Distribution in a Jet Engine...

Tom...please refer to my previous posts in this thread...I have even drawn little sketches to illustrate the physics...I do have a degree in aerospace engineering and I work in the industry...

It is no secret how an intake produces thrust...this subject is covered in all textbooks...here is a book from Rolls Royce that has an entire chapter devoted to this...you can view the entire book online here...

Rolls Royce - The Jet Engine

Go to Chapter 20...Thrust Distribution...Figure 20-1 on page 208 shows the thrust distribution in the engine...the compressor...diffuser...and burner each make a forward thrust force...or gas distribution as the book calls it...

The turbine section and the jet nozzle make a rearward force or drag...when you subtract all the drag forces from all the thrust forces you end up with the engine's overall thrust...

This is the principle I have tried to explain in detail...it has to do with the fact that the sum of momentum and the pressure times area product is greater at the aft end of the compressor and diffuser and burner...than it is at the forward end...creating a force in the forward direction...

An engine inlet is a diffuser...that is why it makes a forward force...please read the chapter and try to do the math in there and you will understand how it works...

Regards,

Gordon.
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