Book contents
- Frontmatter
- Contents
- Foreword by Dr Mike Hicks
- Preface
- Acknowledgements
- 1 Introduction
- 2 The physical metallurgy of nickel and its alloys
- 3 Single-crystal superalloys for blade applications
- 4 Superalloys for turbine disc applications
- 5 Environmental degradation: the role of coatings
- 6 Summary and future trends
- Index
3 - Single-crystal superalloys for blade applications
Published online by Cambridge University Press: 01 September 2009
- Frontmatter
- Contents
- Foreword by Dr Mike Hicks
- Preface
- Acknowledgements
- 1 Introduction
- 2 The physical metallurgy of nickel and its alloys
- 3 Single-crystal superalloys for blade applications
- 4 Superalloys for turbine disc applications
- 5 Environmental degradation: the role of coatings
- 6 Summary and future trends
- Index
Summary
The gas turbine consists of many different pieces of turbomachinery, but the rows of turbine blading are of the greatest importance since many engine characteristics, for example the fuel economy and thrust, depend very strongly on the operating conditions which can be withstood by them. Thus very arduous temperatures and stresses are experienced by the materials employed, which are pushed near to the limits of their capability. This is particularly the case for the high-pressure blades, which are located nearest to the hot gases emerging from the combustion chamber. Their function is to extract work from the gas stream and to convert it to mechanical energy in the form of a rotating shaft, which drives the high-pressure compressor.
A consideration of the operating conditions experienced by the high-pressure turbine blades in a large civil turbofan engine, such as the Rolls-Royce Trent 800 or General Electric GE90, confirms this point. The temperature of the gas stream is about 1750 K, which is above the melting temperature of the superalloys from which the blades are made. The high-pressure shaft develops a power of about 50 MW – hence, with about 100 blades, each extracts about 500 kW, which is sufficient to satisfy the electricity requirement of about 500 homes. Each row of blades is expected to last at least 3 years, assuming they operate at 9 h/day. This is equivalent to about 5 million miles of flight, or ~500 circumferences of the world.
- Type
- Chapter
- Information
- The SuperalloysFundamentals and Applications, pp. 121 - 216Publisher: Cambridge University PressPrint publication year: 2006
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