A still from a simulation produced
during a study on lean, hydrogen-air mixtures showing a cutaway profile of the
concentration of hydroxyl molecules (that are produced and consumed at the
flame). Red areas mark regions of intense combustion; fine gray-blue vortex
structures at the base of the flame mark turbulence.
Close-up of a still from a simulation
produced during a study on lean, hydrogen-air mixtures showing a cutaway
profile of the concentration of hydroxyl molecules (that are produced and
consumed at the flame). Red areas mark regions of intense combustion; fine
gray-blue vortex structures at the base of the flame mark turbulence.
Combustion produces over 80 percent of
the nation's energy, but also a large percent of air pollutants. Robert Cheng
and colleagues at Lawrence Berkeley National Laboratory (LBNL) developed a low-swirl
burner for turbines and furnaces. Requiring no pilot light or moving parts, it
is a nozzle fitted to the end of a fuel pipe. Inside the nozzle, airfoil-like
vanes make the flow of fuel swirl and expand radially as it exits the pipe,
creating a local stagnation region where a bowl-shaped flame can sit
indefinitely. If enough swirl is added to hold the flame steady, while not
trapping any hot combustion products in a recirculation above the flame, it can
burn lean with ultralow emissions. This simulation was created by LBNL's Center
for Computational Sciences and Engineering and the National Energy Research
Scientific Computing Center.
(Date of Images: 2010)
Credit: Lawrence Berkeley National
Laboratory
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