Jet Engine: Turbine Blades and Temperature

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Discussion Overview

The discussion focuses on the environmental conditions that turbine blades in jet engines must withstand, particularly in relation to the materials used and their properties. Participants explore the effects of high temperatures, pressures, and mechanical stresses on turbine blade performance, referencing specific alloys and manufacturing processes.

Discussion Character

  • Technical explanation
  • Exploratory
  • Debate/contested

Main Points Raised

  • Some participants mention that turbine blades in jet engines, such as those in the Trent Engine, are exposed to high temperatures, potentially reaching up to 2000 degrees Fahrenheit, but question the exact temperatures experienced by the blades.
  • Inconel 718 and 738, along with CMSX-4, are proposed as suitable materials for turbine blades, with some noting the importance of Rhenium content in CMSX-4.
  • Participants discuss the significance of manufacturing processes, particularly the use of single crystal formulations for hot section blades.
  • There is mention of the cooling mechanisms in turbine design, such as the use of vent holes to allow cooler air to flow over the blades, which helps manage temperature and prevent stress cracks.
  • Some participants express interest in the evolution of turbine blade materials over time, particularly regarding their melting points, strength, and resistance to fatigue and creep.
  • Concerns are raised about the balance of turbine blades and the implications of supersonic speeds at the tips of the blades, which can lead to shock waves and temperature increases.
  • Several participants seek resources and statistics on the historical development of turbine blade materials and their properties, noting the difficulty in finding comprehensive information.

Areas of Agreement / Disagreement

Participants generally agree on the high temperatures turbine blades must withstand and the types of materials used, but there is no consensus on specific temperature variances or the historical evolution of materials. Multiple competing views on the properties and performance of different materials remain unresolved.

Contextual Notes

Participants express uncertainty regarding the exact temperatures turbine blades experience and the specific environmental factors that must be considered in material selection. There are also limitations in available resources and statistics on the evolution of turbine blade materials.

Who May Find This Useful

This discussion may be of interest to students and professionals in aerospace engineering, materials science, and those studying jet engine design and performance.

  • #31
Look at my item #2 again. This is a very specialized area especially in the design and manufacturing end. There are many proprietary designs and processes involved. The technical knowledge in many cases is not found in book and must be learned through experience. Start ups in other countries will not have that and will have a huge learning curve to make up for.
 
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  • #32
mgb_phys said:
...building a jet aircraft isn't too tricky.
Ummm...
 
  • #33
quick quesion:
In terms of technical know-how and technological capabilities in the field of material science, is there any similarity between jet vanes used for thrust vectoring of rockets and the turbine blades in jet engines?
Are the two related to each other at all or are they completely irrelavant?
Which one is more sophisticated?
Would the capability to make one "imply" the capability to make the other?
 
  • #34
FredGarvin said:
Ummm...

Compared to a nuke, nuclear powered subs, satelite launchers, cars capable of more than 20mpg and other stuff that 'backward' countries like India and China are capable of.
 
  • #35
Soorena said:
quick quesion:
In terms of technical know-how and technological capabilities in the field of material science, is there any similarity between jet vanes used for thrust vectoring of rockets and the turbine blades in jet engines?
Are the two related to each other at all or are they completely irrelavant?
Which one is more sophisticated?
Would the capability to make one "imply" the capability to make the other?
Rockets usually used gimbled rocket motors or small rocket motor to 'steer' the rocket. Control surfaces on aircraft and some rockets are made of the lighest possible material and usually do not operate at high temperature - except for those vehicles traveling well beyond supersonic. By contrast turbine blades in a jet engine operated at very high temperatures.

There is a great deal of 'art' in perfecting an alloy composition that retains high strength, toughness and creep resistance at high temperature.


China and India are not backward countries. They have considerable expertise in many high tech areas.
 
  • #36
Astronuc said:
Rockets usually used gimbled rocket motors or small rocket motor to 'steer' the rocket. Control surfaces on aircraft and some rockets are made of the lighest possible material and usually do not operate at high temperature - except for those vehicles traveling well beyond supersonic. By contrast turbine blades in a jet engine operated at very high temperatures.

There is a great deal of 'art' in perfecting an alloy composition that retains high strength, toughness and creep resistance at high temperature.


China and India are not backward countries. They have considerable expertise in many high tech areas.

Thanks for the reply.
However I am pretty sure that apart from gimbled engines, "jet vanes" too are used for steering. Some times graphite and sometimes graphite reinforced ceramic composite jet vanes are used.
If you google the phrase "graphite reinforced ceramic composite jet vanes" you will find a blog which is about proliferation control. Over there they talk about advanced composite material jet vanes which are used to steer rockets.
The blog is contributed to by rocket scientists so it is fairly reliable in terms of technical information as far as rockets go.
So I am sure that jet vanes are used for steering rockets and I was just wondering if the technology for making such composite material is related to the technology of making turbine blades?
If there is any similarity in between, would the technical know-how as to make one imply the ability to make the other? or are they completely unrelated to each other?
 
  • #37
To Astronuc:

By the way the graphite reinforced ceramic which is used for making jet vanes (in general ANY materials used for making jet vanes for the purpose of steering the rockets) has to be able to withstand EXTREME temperatures and very harsh environment.
 
  • #38
Look up the German V-2. It used graphite vanes for thrust vectoring. It has to have been reused since then.

The black shapes in the attached picture are the vanes:
infopic05.jpg
 

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