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INFLUENCE OF INJECTION PRESSURE AND SWIRL
CHAMBER DIAMETER ON JET-SWIRL ATOMIZER SPRAY ANGLE
Zulkifli Abdul Ghaffar, Salmiah Kasolang and Ahmad Hussein Abdul
Hamid
Faculty of Mechanical Engineering, Universiti Teknologi MARA
(UiTM), Shah Alam,
Selangor
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Liquid atomization
Background
Objective
Apparatus & Measurement
Results & Discussions
Conclusions
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Applications
Food coating
Fuel injection
Fire suppression
Nasal spray Perfume
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Definiton: A process of disintegrating bulk liquid into
sprays
Acquired through a device called the atomizer
E.g. jet-swirl atomizer, pneumatic atomizer, ultrasonic
atomizer
Jet-swirl atomizer An atomizer in which the liquid is
swirled by means of swirl-generating
vanes before discharge the atomizer
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Hamid et al & Laryea et al Studied the influence of
injection pressure on the spray
angle of pressure-swirl atomizer
Hussein et al Studied the influence of orifice diameter towards
spray
angle of jet-swirl atomizer
Rizk and Lefebvre Studied the influence of swirl chamber
diameter and
operating conditions on spray angle of pressure-swirl
atomizer
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Influence of swirl chamber diameter on pressure-swirl atomizer
spray angle has been studied but not on jet-swirl atomizer spray
angle
Importance of wider spray angle
Wider spray distribution
In combustion, increase in spray angle increases the exposure of
the droplets to the surrounding air or gas, leading to improved and
higher rates of heat and mass transfer
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To investigate the influence of injection pressure and swirl
chamber diameter variation on spray angle of a newly designed
jet-swirl atomizers
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Atomizer geometries & operating principles
Ato
miz
er
no
.
Geometrical parameters
Vane tip angle,
( )
Swirl chamber diameter, ds (mm)
Swirl chamber length, ls
(mm)
Discharge orifice
diameter, do (mm)
Discharge orifice
length, lo (mm)
1 45 25 40 2.5 5
2 45 40 40 2.5 5
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Cold flow test-rig Lab scale
Camera
High-speed camera at 1000fps
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Spray angle measurement Video recordings converted to sequence
of images
Conversion to binary form
Facilitate spray visualization
Measurement of spray angle
Angle tool in ImageJ
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Effect of liquid injection pressure Upon increased, spray angle
shows fluctuation with
ds=25mm but remains steady with ds=40mm
Effect of swirl chamber diameter Smaller diameter results in
larger spray angle
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Relation of liquid injection pressure to volume flowrate
Increased with increase of injection pressure
Almost similar values for both swirl chamber diameter
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Based on the study, it was found that the increment of injection
pressure and reduction of swirl chamber diameter led to the
production of a wider spray angle.
In addition, the spray angle was found to be unaffected by the
changes of volumetric flow rate.