This document discusses turbine blades used in jet engines and gas turbine generators. It covers the design considerations for turbine blades including geometry, cooling vanes, and attachment interfaces. Material selection is critical due to the extremely high operating temperatures, with titanium and nickel alloys currently used. Manufacturing methods include investment casting and electro-chemical machining. The document provides details on applications, design factors, materials requirements, and manufacturing processes for turbine blades.

1. Turbine Blades
Terry Andersen
Nathan Stastny
ME 372
Brigham Young University
Fall 2001

2. Overview
• Applications
• Design Considerations
• Material Considerations
• Manufacturing Processes
• Review
• Questions

3. Applications
• Gas Turbine Generators
• Jet Engines

4. Rolls Royce
Rolls Royce Trent
Turbine Blades

5. Design Considerations
• Geometry
• Cooling Vanes
• Attachment Interface
• Safety Factors

6. Geometry
• Strength / Fatigue Life
• Each row will be different
• Air Flow (CFD Package)
• Machineability
General Turbine Blade Shape

7. Cooling Vanes
• Blades must be kept cool
• Often operate near the metal melting
point
• An increase of only 17 C can
decrease the engine life by half
• Cool (300 C ) air is run out of the
blades through small holes (vanes),
keeping the blades from melting.

8. Pic

9. Attachment
• Keep Stress Concentrations Low
• “Fir Tree” Attachment
– Reduced stress
concentrations
– Easy replacement
– Also known as the
“Christmas Tree”

10. Safety Factors
• Higher S.F. is usually the best.
• But what if the engine runs out of control at
speeds higher than intended?
• The energy of the rotating blades goes up with ω2
• What happens if the blades brake at 10%
overload? 20%, 30%, 40%, 50% ?
• Too much energy and the blades might break
through the engine shroud and into the fuselage.

11. Quick Video
Boeing 777
Engine Test

12. Material Considerations
• Environment
• Creep
• Current Materials Used
• Materials In Research

13. Environment
• Air Temperature: Between 850 and 1600 °C
• Melting Temperature:
– Steel:1400C
– Nickel Alloy: 1200C
– Titanium:1650C
• Turbine RPM: Appx. 20,000 rpm

14. Creep
• Turbine blades elongate during their life
• Tip clearance
• Result of environment and grain structure
• Soft “abradable” lining
• Directional solidification (cooling)
• Single crystal structure

15. Current Materials Used
• Initially Steel
• Nickel Alloys
• Most common material is Titanium
• Laser peening
• Ceramic Coatings

16. Material In Research
• Ceramic blades
• Carbon composite blades
– Noise reduction
– Light weight

17. Manufacturing Processes
• Machining (not too common)
• Investment Casting
– Secondary machining
• Electro-Chemical Machining
– Single operation

18. Design Sites
1. www.pccsmp.com (manufacturing)
2. www.turboblades.com (manufacturing)
3. www.giverin.demon.co.uk/NewFiles/HT
WTurbines.html (information)
4. www.gas-turbines.com/begin (information)
5. www.pratt-whitney.com (engine manufacturer)

19. Review
• Applications:
– Jet Engines
– Gas Turbine Generators
• Design Factors:
– Geometry
– S.F.
• Materials:
– Very high temperatures
– Titanium
• Manufacturing:

20. Questions

21. Terry
Nathan
Dr. Chase
Squadron Commander
Special thanks to all
those who didn’t
believe in us, but whom
we’ve proved wrong.