Turbines

Image source: http://www.ge-energy.com/content/multimedia/_files/photos/Tool_Gas%20Turbine%20Performance%20Estimator.jpg

Why turbines??

• Turbines provide mechanical energy to the compressor.

• It increases the efficiency of jet engine.

Image source: http://www.turbomachinerymag.com/blog/content/ivan-article-series-part-1

Turbine Blades

• Made of superalloys.• Different methods of cooling

• Internal cooling• External cooling

Image source: http://encryptechno.com/tag/axial/

Image source: http://www.laserdesign.com/services/3d_laser_scanning/project_news/280/

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• Generation of stresses– High centrifugal force(turbines run at thousands of

rpm)– High temperature– Fluid forces

• High temperature causes corrosion failure• Vibration causes fatigue failure• Blade materials: U-500, Inconel, GTD-111, EPM-

102

Source: Mechanical design of turbojet engines, University of Liege

Afterburner

A U.S. Navy F/A-18 Hornet being launched from the catapult on full afterburner.

Image source: http://en.wikipedia.org/wiki/File:FA18_on_afterburner.jpg

More about afterburners

• Increases thrust

• Very high fuel consumption

• Efficiency decreases

• Good for turbofan engines

Afterburner of Eurofighter typhoon

MiG-23 Afterburner

Image source: http://en.wikipedia.org/wiki/Afterburner

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