NASA’s new study concludes that by using biofuels in jet engines, 50% to 70% of particle emissions can be reduced from their exhaust. This promises a positive change in the earth’s environment as well as in airline economics.
The study was conducted by NASA that was part of an international research program involving several agencies from Canada and Germany. A detailed version of the study can be found in a journal called “Nature”.
In the years from 2013 to 2014, flight tests were conducted in Edwards, California at the Armstrong Flight Research Center. NASA used different fuels in commercial airlines to collect data on contrails generated at certain altitudes, emissions and engine performance. These tests were for a separate category called ACCESS (Alternative Fuel Effects on Contrails and Cruise Emissions Study).
Contrails, also known as vapor trail is produced when the engine’s exhaust combines with atmospheric cold air at typical cruise altitudes. The vapor trail takes an ice crystal form and is composed of water.
What the researchers are interested in is persistent contrails. These contrails are extensive and long-lasting and are different to the clouds normally found in the sky. They believe that these long-lasting contrails are the key factors to what influences the earth’s environment.
Bruce Anderson, the scientist at the Langley Research Center, who is working on the ACCESS project, says that soot emissions are also one of the major drivers of vapor trail formation and properties. He believes that particle reduction measured with ACCESS will reduce ice crystals, due to which the impact of contrails on the earth’s environment will be minimized.
The thin, wispy strands of cirrus clouds pose a larger threat to the earth’s atmosphere compared to the carbon dioxide released from airlines that was first experienced in the flight introduced by Wright Brothers.
ACCESS involved the DC-8 workhorse by NASA, which was flown at a height of 40,000 ft. The craft’s four engines were working on a blend of 50% hydro processed fuel of fatty acids and ester from the plant oil called “Camelina” and 50% aviation fuel. The aircraft was flown by three different people from 300 ft to above 20 miles. Depending on the distance, emission measurements were taken on the use different types of fuels.
Nature’s lead author, Rich Moore described the tests as a huge breakthrough in measuring contrails. He said, “This was the first time we have quantified the amount of soot particles emitted by jet engines while burning a 50-50 blend of biofuels in flight”.
The aircrafts used in the trails included German Aerospace Center’s (DLR) Falcon 20-E5 jet, National Research Council of Canada’s CT-133 jet and the HU-25C Guardian jet by NASA based at Langley.
Hans Schlager, who is Nature’s co-author working at the DLR Institute of Atmospheric Physics says that in order to have accurate data about the contrails, they need to have skilled crew members and gear that has given accurate results in the past. He believes that the DLR Falcon is the best aircraft to investigate emissions because since 2000, it has accurately measured contrails and emissions of commercial airlines.
NASA plans to continue its research to demonstrate how biofuels can benefit aircrafts, as well as the earth’s environment. NASA’s goal is to use its “supersonic X-plane” to demonstrate the benefits of biofuels.