Abstract
Measurements of minimum ignition energy were carried out on kerosine
sprays injected into a flowing air stream under conditions of atmospheric
pressure and temperature. All the measurements were performed using
optimum values of spark duration and with the spark gap adjusted
to slightly exceed the quenching distance. Tests were carried out
at air velocities up to 50 m/sec on five simplex swirl atomizers
designed to produce fuel drops ranging in Sauter Mean Diameter (SMD)
from 30 to 100 mum. Ignition was accomplished using capacitance
sparks whose energy level could be varied in steps from 3 to 130
mJ. The results obtained clearly demonstrate that by far the most
important factor influencing minimum energy is fuel drop size. Ignition
performance is improved by increase in spark energy, but very large
additional amounts of energy are needed to compensate for even a
slight deterioration in atomization quality. It is shown that, for
any given atomizer, an increase in velocity can actually improve
the weak ignition limit, due to the beneficial effect of velocity
on atomization quality. If, however, the fuel drop size is maintained
constant, then increase in air velocity has a detrimental effect
on the weak ignition limit, in agreement with results obtained on
gaseous mixtures.
Users
Please
log in to take part in the discussion (add own reviews or comments).