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Published on June 18th, 2015 | By: April Gocha, PhD

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Plan to cut airplane emissions could mean big things for ceramic matrix composites

Published on June 18th, 2015 | By: April Gocha, PhD

[Image above] Boeing’s composite 787 Dreamliner. Credit: Tim Wang; Flickr CC BY-SA 2.0

 

 

The U.S. Environmental Protection Agency is gearing up to develop standards to reduce emissions from airplanes, according to a recent NY Times article.

 

Although the announcement comes with its own dose of healthy concerns and criticism—largely anticipated fears that the down-the-road regulations will do too little, too late—the announcement is the first step toward checking airplane emissions.

 

And, because that class of emissions is barely regulated currently, any step is needed considering the growing pace of air travel, which shows no signs of slowing

 

Worldwide commercial air travel annually contributes some 700 million tons of carbon dioxide to the atmosphere, according to a Science news article also covering the topic. “If aviation were a country, it would rank seventh in world emissions, just behind Germany and ahead of South Korea. And U.S. aircraft account for nearly one-third of the world’s aviation emissions,” the article cites.

 

So how will airlines be able to comply?

 

Just like the auto industry, one relatively simple way to slash emissions is to make vehicles lighter.

 

Lightweighting is nothing new to the airline industry. Planes that use lighter materials, namely composites, have been creeping into the industry for some time.

 

One notable example is the composite-clad body of Boeing’s 787 Dreamliner.

 

“Only 1% of the weight of Boeing’s 747 jumbo jet came from composite parts when that jet was introduced in 1969. That increased to 11% by 1995 on the 777, which has an all-composite tail section…Composites now account for half of the 787’s weight, which, together with more efficient engines, cut fuel consumption by 20%,” according to a NY Times article about the jet.

 

But the composite trend is going to have to continue to keep reaching new lows in weight and new highs in engine efficiency to considerably reduce those 700 million tons of emissions.

 

Accordingly, lighter composite parts have infiltrated other parts of jets, too—GE is putting ceramic matrix composites (CMCs) into jet engines with recent successful tests of moving CMC components.

 

GE’s CMC turbine blades are as strong as metal, but with higher temperature resistance in a package that’s just one-third the weight of traditionally used nickel alloys.

 

“Going from nickel alloys to rotating ceramics inside the engine is the really big jump. But this is pure mechanics,” says Jonathan Blank, general manager of CMC and advanced polymer matrix composite research at GE Aviation, in a GE Aviation press release. “The lighter blades generate smaller centrifugal force, which means that you can slim down the disk, bearings, and other parts. CMCs allow for a revolutionary change in jet engine design.”

 

See how GE Aviation manufactures its revolutionary CMCs in the short video below.

Credit: GE Aviation; Youtube

 

GE is not the only company working on CMC advances for airplanes. Boeing also recognizes the potential of CMCs with the recent completion of its own tests of new composite engine nozzles.

 

Regardless of the specific component, however, composites are certain to continue an upward trajectory in the aerospace industry.

 

Aerospace applications comprise the largest segment of the growing CMC market, which is predicted to expand to $2.4 billion by 2019, according to a recent market report. Those aerospace applications are predicted to grow at an annual rate of 14.06% from 2014–2019.

 

Imposed regulations to cut airplane emissions could push that rate even higher, too.

 

But is there a limit to how efficient planes can get? Yes, according to a Wired article from a few years ago.

 

According to the article (which also provides a great explanation of the physics behind flight), airplanes are already really efficient. But the best way to increase overall efficiency is to advance engine technology.

 

Although author Aatish Bhatia says that planes can’t realistically shrink much in size to improve efficiency, Bhatia is not considering that pounds can still be shed with the help of advanced materials.

 

Other improvements can be made, too. The article adds that “new manufacturing techniques could cut the amount of drag on the plane’s surface, but these improvements would only raise efficiency by about 10%.” Still, combining that 10% gain in efficiency with those achieved by making planes lighter can equal rather significant overall savings in fuel efficiency.

 

Even a 15% reduction in airplane emissions would spare some 105 million tons of carbon dioxide from entering the atmosphere. I think that’s certainly an effort worth working towards. And I’m not alone

 

 


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