1. JET ENGINE WEIGHT OPTIMISATION TECHNIQUES
USED IN INDUSTRY
Take home message:
Using lightweight materials has the greatest potential in reducing the weight of a
jet engine, key reasons and ideas are:
• The LEAP engine which uses ceramic alloys in the turbine blades is an example
of how lightweight materials are being used in areas of highest pressure. This
shows that with progressing research, the use of lightweight materials becomes
less restricted.
• Future Nano-technology could allow materials to be more durable and lighter.
• Lightweight materials as a whole reduce weight most effectively and thus are
more cost effective in the long term.
Why is an engine’s weight important?
An aeroplane’s jet engine can hold significant weight, particularly as jet engines are increasing in size
and mass. Engineers are developing different techniques to reduce the weight of a jet engine, this
would allow money to be saved on fuel and thus increase the likelihood of airlines purchasing the
engine.
Technique 2:
Lightweight
Materials
Technique 1:
Engine
Design
Reducing parts:
Fewer components would mean
less weight. Engineers aim to
ensure there is no ‘dead’ weight
in the engine and that minimal
components/stages are used.
An example of this is in the Rolls
Royce Advance Prototype which
has fewer stages in the
compressor.
Limitations of using lightweight
materials:
• Restricted use in the engine.
Lightweight materials cannot survive
extreme forces in compressors and high
temperatures in the turbine.
Benefits of Lightweight materials:
• Although expensive to manufacture, its
effectiveness in reducing engine weight
can save money on fuel in the long
term.
• Research into lightweight materials is
common among many industries and so
there are always new innovations.
Limitations of Engine design:
• The use of material cut-outs are very
restricted, since very low stresses are
mainly situated in the root of a blade
where centrifugal forces are minimal.
• Reducing the parts of a jet engine is also
restricted since aeroplanes are getting
larger, this could have an effect on the
thrust and efficiency of a jet engine.
Turbofan engines:
Some of many example of lightweight materials
being used in jet engines is the Rolls Royce Advance
engine, the GEnx engine and the CFM International
LEAP engine. Most models use Carbon fibre
materials for the main body of the fan blade, while
the LEAP engine also uses an innovative ceramic
matrix composites in the turbine. Although jet
engines are getting increasingly heavier, these
methods reduce the most amount of weight. For
example, the Rolls Royce advance is forecasted to
being 750lb lighter due to its Carbon fibre material.
Material Cut-outs:
This weight
optimisation technique
researched by Altair
engineering involves
cutting out material in
blades in regions of low
stress without
endangering the
structural integrity of
the blade. This is said
to achieve a maximum
of only 10% weight
reduction.
References and acknowledgements
Altair Engineering, Weight optimization of turbine blades, J.S.RAO Bhaskar Kishore Vasantha Kumar, 2011
Rolls Royce official Advance website
GE Aviation official website
AEROSPACE magazine, Royal Aeronautical Society, January 2016 edition, page 14-15.
Pratt &Whitney official website.
CFM international official website
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