Study of Gas-Centered Coaxial Injector Using Jet …
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liquid jet tends to disintegrate into larger drops with lesser penetration. From Fig. 3
it is also evident that as MFR increases, variation in the drop sizes at downstream
locations increases. At low MFR, the differences between the drop sizes (SMD) at
downstream positions are less. At higher MFR, the difference between the drop sizes
increases. At low MFR, due to high gas velocity, atomization is very fine and the
spray coming out from the injector is very dense. This is why no major difference
in SMD was observed at different downstream positions. But at higher MFR, the
velocity of the gas is comparatively less and the disintegration of jet is basically due
to the momentum of the jet itself. Hence, in this case, differences in the value of
SMD were observed at different downstream positions.
The distances from the exit of the injector to the laser beam of the Malvern Particle
Analyzer were kept at 25, 50, 75, 100 and 125 cm. From Fig. 3, it is clear that at
all MFR as the downstream position increases, the drop size (SMD) also increases.
At nearer downstream positions, the velocity of the spray is high and at further
downstream positions, the velocity is less due to resistance of the air. Figure 3 shows
that there is no major difference in SMD at initial three positions (25, 50 and 75 cm).
But the SMD is high at other two further positions (100 and 125 cm), which means
after a certain point of downstream positions the drop size increases due to the effect
of coalescence. Increase in drop size after reaching a minimum value may be due to
the adhesion of decelerated particle which experienced momentum loss due to the
drag effect and momentum exchange with gas streams.
Figure 4 Show the variation of SMD with Weber number of gas flow. From this
graph we see that as Weber number increases, drop size decreases at all downstream
positions. At high Weber number, the velocity of the gas and the relative velocity
were high. Figure 5 shows the variations of SMD with relative velocity between gas
flow and liquid jet. In case of higher relative velocity the disintegration of liquid jet
is perfect atomization is fine. Therefore, at higher Webber Number atomization is
better and drop size is lower. Increase in Weber number means the disruptive force
increases and the liquid jet disintegrates into drops easily. As seen in Fig. 6a–f as
Fig. 4 Variation of SMD with different Weber No
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liquid jet tends to disintegrate into larger drops with lesser penetration. From Fig. 3
it is also evident that as MFR increases, variation in the drop sizes at downstream
locations increases. At low MFR, the differences between the drop sizes (SMD) at
downstream positions are less. At higher MFR, the difference between the drop sizes
increases. At low MFR, due to high gas velocity, atomization is very fine and the
spray coming out from the injector is very dense. This is why no major difference
in SMD was observed at different downstream positions. But at higher MFR, the
velocity of the gas is comparatively less and the disintegration of jet is basically due
to the momentum of the jet itself. Hence, in this case, differences in the value of
SMD were observed at different downstream positions.
The distances from the exit of the injector to the laser beam of the Malvern Particle
Analyzer were kept at 25, 50, 75, 100 and 125 cm. From Fig. 3, it is clear that at
all MFR as the downstream position increases, the drop size (SMD) also increases.
At nearer downstream positions, the velocity of the spray is high and at further
downstream positions, the velocity is less due to resistance of the air. Figure 3 shows
that there is no major difference in SMD at initial three positions (25, 50 and 75 cm).
But the SMD is high at other two further positions (100 and 125 cm), which means
after a certain point of downstream positions the drop size increases due to the effect
of coalescence. Increase in drop size after reaching a minimum value may be due to
the adhesion of decelerated particle which experienced momentum loss due to the
drag effect and momentum exchange with gas streams.
Figure 4 Show the variation of SMD with Weber number of gas flow. From this
graph we see that as Weber number increases, drop size decreases at all downstream
positions. At high Weber number, the velocity of the gas and the relative velocity
were high. Figure 5 shows the variations of SMD with relative velocity between gas
flow and liquid jet. In case of higher relative velocity the disintegration of liquid jet
is perfect atomization is fine. Therefore, at higher Webber Number atomization is
better and drop size is lower. Increase in Weber number means the disruptive force
increases and the liquid jet disintegrates into drops easily. As seen in Fig. 6a–f as
Fig. 4 Variation of SMD with different Weber No