Environmental Engineering Reference
In-Depth Information
5 Material Challenges
With the demise of the Concord aircraft, supersonic air transport came to a halt for
commercial aviation. However, research and development of new engines for
supersonic aircraft for military applications continues, and eco-friendly engines (low
emission and noise) that operate at higher temperatures and speed pose additional
challenges. Though commercial hypersonic aviation may not happen in the next few
years, the challenges need to be solved as early as possible. As the speed, altitude,
and operational temperatures increase, new materials need to be developed both for
airframe and engine components. Hypersonic research has attracted worldwide
interest, and a number of bilateral and multilateral collaborations have been signed
off by several countries, and joint laboratories and development centers are already
in operation. The major issues are wall cooling, environmental effects, high heat
release rates, high speed
flows and wall interactions, fatigue, crack propagation,
abrasion, and drag. In order to solve these, research should focus on new light weight
and stronger materials with fatigue and abrasion resistance. Further, self-healing
coatings that heal themselves when a crack or skin damage occurs, is of interest.
Other coatings include
fl
flexible coatings that will not crack when the base material is
subjected to thermal and mechanical fatigue.
Research on materials and coatings for hypersonic applications will naturally
bene
fl
t in manufacturing other products for longer life and eco-friendly operation.
6 Conclusions
As the energy landscape is changing, it is not prudent to depend on fossil fuels
alone for the future. It is equally important to develop alternate sustainable fuels
from land and marine sources, as
finding new gas and oil resources. The selection
of alternate fuels depends upon the natural resources and geography of the par-
ticular country. For example for countries such as Malaysia and Philippines with the
extensive shore lines, algae based fuel is a natural choice. Nations with large
available land areas such as the United States, India, and China, plant-based fuels
present a reliable opportunity. The challenges in the production and utilization of
alternate fuels, such as biofuels, must be thoroughly addressed before production to
meet public and industry demand. Since economy plays a major role in the
development of alternate fuels, attention should be paid to focus only on promising
candidate fuels. Tailored fuels for speci
c applications are still in need, and clever
means of converting the chemical energy contained in the fuels with maximum
conversion ef
ciencies and minimum chemical and noise pollution need to be
discovered. Functional materials, tailored coatings, and surface treatments to satisfy
individual application requirements should be given utmost priority by the materials
research community, as the future energy conversion systems will be operating in
more demanding environments.
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