Piloted Ignition of a Slick of Oil on a Water Sublayer: The Effect of Weathering.
Piloted Ignition of a Slick of Oil on a Water Sublayer:
The Effect of Weathering.
Wu, N.; Kolb, G.; Torero, J. L.
Combustion Institute, Symposium (International) on
Combustion, 27th. Proceedings. Volume 2. August 2-7,
1998, Boulder, CO, Combustion Institute, Pittsburgh, PA,
2783-2790 pp, 1998.
Sponsor:National Institute of Standards and Technology,
combustion; oil spills; pilot ignition; water;
temperature measurements; flow visualization; ignition
delay; crude oil; weather effects
Piloted ignition of a slick of oil on a water sublayer
has been experimentally studied. The objective of this
work is to provide a tool that will serve to assess a
fuel's ease to ignite under conditions that are
representative of oil spills. The fuel is exposed
suddenly to external radiation to increase its
temperature until ignition occurs. The strength and
geometrical placement of the pilot were chosen to
minimize gas-phase induction time and heat feedback from
the pilot to the fuel surface. Temperature
measurements, flow visualization, and ignition delay
time are used to characterize piloted ignition, and an
existing one-dimensional heat transfer model is used to
correlate the experimental results. Two different crude
oils and SAE 3OW oil were used for these experiments.
Crude oils were tested in their natural state and at
different levels of weathering. It was observed that
the ignition delay time is a strong function of the flow
structures formed both in the liquid and gas above the
pool. Piloted ignition is inhibited by premature
boiling of the water sublayer, and weathering
significantly increases the ignition delay time. It was
determined that a critical heat flux for ignition could
be obtained and better serve as a parameter to
characterize the fuel propensity to ignite in the
presence of a strong pilot. The minimum heat flux that
will permit ignition before boiling of the water
sublayer occurs also needs to be considered.