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Flame propagation in heterogeneous mixtures of fuel drops and air
Combustion and Flame, 66 (2): 193--210 (ноября 1986)
DOI: 10.1016/0010-2180(86)90091-X
Аннотация
An experimental study is conducted on the influence of fuel chemistry
on the flame speeds of flowing mixtures of fuel drops in air at atmospheric
pressure. Air is supplied at room temperature to a 10 cm2 test section
which is fitted with quartz windows to provide optical access to
the flame. Sixty-four evenly spaced airblast atomizers ensure a uniform
fuel distribution in the mixture entering the flame zone. Variation
in mean fuel drop size is accomplished by varying the air flow rate
to the airblast atomizers.Schlieren pictures of the flame provide
the basic data for the measurement of flame speed, using the angle
method. The fuels employed include a conventional No. 2 fuel oil,
plus various blends of JP7 with stocks containing single-ring and
multiring aromatics. For all fuels the measured flame speed is found
to be inversely proportional to SMD above some critical size, indicating
that in this range of large drop sizes evaporation rates are controlling
to flame speed. The fuels exhibiting the highest flame speeds are
those containing multiring aromatics. This is attributed to the higher
radiative heat flux emanating from their soot-bearing flames, which
enhances the rate of evaporation of the fuel drops approaching the
flame front.
