NASA Study Confirms
Biofuels Reduce Jet Engine Pollution
EDITOR’S
NOTE: Here is more science work under serious attack by Donald Trump’s budget
cuts that target research of this kind. That probably won’t bother Richmond
state Representative Justin Price (R), one of those right-wing nuts who
thinks that the government is using chemicals against the population that are
mixed in with jet aircraft’s contrails.
Using biofuels to help power jet engines reduces particle
emissions in their exhaust by as much as 50 to 70 percent, in a new study
conclusion that bodes well for airline economics and Earth’s environment.
The findings are the result of a cooperative international
research program led by NASA and involving agencies from Germany and Canada,
and are detailed in a study published in the journal Nature.
During flight tests in 2013 and 2014 near NASA’s Armstrong Flight
Research Center in Edwards, California, data was collected on the effects of
alternative fuels on engine performance, emissions and aircraft-generated
contrails at altitudes flown by commercial airliners. The test series were part
of the Alternative Fuel Effects on Contrails and Cruise Emissions Study, or
ACCESS.
Contrails are produced by hot aircraft engine exhaust mixing with
the cold air that is typical at cruise altitudes several miles above Earth's
surface, and are composed primarily of water in the form of ice crystals.
"Soot emissions also are a major driver of contrail
properties and their formation," said Bruce Anderson, ACCESS project
scientist at NASA’s Langley Research Center in Hampton, Virginia.
"As a
result, the observed particle reductions we’ve measured during ACCESS should
directly translate into reduced ice crystal concentrations in contrails, which
in turn should help minimize their impact on Earth’s environment."
That’s important because contrails, and the cirrus clouds that
evolve from them, have a larger impact on Earth’s atmosphere than all the
aviation-related carbon dioxide emissions since the first powered flight by the
Wright brothers.
The tests involved flying NASA's workhorse DC-8 as high as 40,000
feet while its four engines burned a 50-50 blend of aviation fuel and a
renewable alternative fuel of hydro processed esters and fatty acids produced
from camelina plant oil.
A trio of research aircraft took turns flying behind
the DC-8 at distances ranging from 300 feet to more than 20 miles to take
measurements on emissions and study contrail formation as the different fuels
were burned.
"This was the first time we have quantified the amount of
soot particles emitted by jet engines while burning a 50-50 blend of biofuel in
flight," said Rich Moore, lead author of the Nature report.
The trailing aircraft included NASA's HU-25C Guardian jet based at
Langley, a Falcon 20-E5 jet owned by the German Aerospace Center (DLR), and a
CT-133 jet provided by the National Research Council of Canada.
“Measurements in the wake of aircraft require highly experienced
crew members and proven measuring equipment, which DLR has built up over many
years,” said report co-author Hans Schlager of the DLR Institute of Atmospheric
Physics.
“Since 2000, the DLR Falcon has been used in numerous measurement
campaigns to investigate the emissions and contrails of commercial airliners.”
Researchers plan on continuing these studies to understand and
demonstrate the potential benefits of replacing current fuels in aircraft with
biofuels. It’s NASA’s goal to demonstrate biofuels on their proposed supersonic X-plane.
