polish academy of sciences institute of fundamental technological research break-up of liquid jet...
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Polish Academy of Sciences
Institute of Fundamental Technological Research
http://fluid.ippt.gov.pl/conex
Break-up of liquid jet in co-flow experimental study
S. Błoński, P.Korczyk, T.A. Kowalewski
MOTIVATION
Visualization of liquid jet break-up and droplet formation for co-flow
Glycerol jet in air
EXPERIMENTAL SETUP
• Epifluorescent microscope – Nikon ECLIPSE E-50i• High Speed CMOS Camera – PCO 1200.hs (up to 40720 fps;
636fps in full resolution 1280x1024)• Pressure system (gas cylinder with argon, pressure
regulator and conduits, pressure sensor• Two precision syringe pumps
Geometry for jet breakup observationchannel size: 30 x 8 x 10 mm
needle diameter: 0.5 mm
Qe = 1 - 5cm3/s
Qj = 5 - 30mm3/s
EXPERIMENTAL SETUP
Used materials:
1. water-alcohol mixture (5:2) + S50 silicone oil + 1%wt SDS2. water-alcohol mixture (5:2) + S500 silicone oil + 1%wt SDS
Used microscope lens: 4x/NA0.13/WD17.1mm
Liquid jet break-up visualization
Used geometry:
Oil Qe [cm3/s] V e [cm/s] Qj [mm3/s] V j [mm/s]
S50 (50mPas) 1.08 – 3.57 2.16 – 7.14 22 – 33 112.2 – 168.3
S50 (500mPas) 0.92 – 1.72 1.84 – 3.44 5.5 – 33 28.1 – 168.3
Ve and Vj – mean flow velocities based on the channel cross-section and inner nozzle diameter, respectively
Liquid jet break-up visualization
Qj = 22 mm3/sQe = 1.08 cm3/s
Break-up period: 60 ms
Qj = 33 mm3/sQe = 1.08 cm3/s
Silicone oil jet S50Image width corresponds to 3.6mm
Liquid jet break-up visualization
S50 oil + water-alkohol + SDS500 fps
Qj = 22 mm3/s; Qe = 1.1 cm3/s
3.6 mm
Liquid jet break-up visualization
S50 oil + water-alkohol + SDS500 fps
Qj = 33 mm3/s; Qe = 1.1 cm3/s
3.6 mm
Liquid jet break-up visualization
S500 oil + water-alkohol + SDS500 fps
Qj = 28 mm3/s; Qe = 1.3 cm3/s
3.6 mm
Liquid jet break-up visualization
Long, cylindrical jet
Silicone oil jet S50Qj = 22 mm3/sQe = 2.7 cm3/s
Image width corresponds to 3.6mm
Disturbed jet
Liquid jet break-up visualization
Qj = 33 mm3/sQe = 1.3 cm3/s
Period of the capillary wave: 60 ms
Filament shortly before droplet separation
Qj = 14 mm3/sQe = 1.47 cm3/s
Break-up period: 240 ms
Silicone oil jet S500Image width corresponds to 3.6mm
Liquid jet break-up visualization
S50 oil + water-alcohol + 1%wt SDS500 fps
Qj = 33 mm3/s; Qe = 2.7 cm3/s
3.6 mm
Liquid jet break-up visualization
S50 oil + water-alcohol + 1%wt SDS500 fps
Qj = 33 mm3/s; Qe = 5 cm3/s
3.6 mm
CONCLUSIONS
The capillary break-up of the liquid jet in co-flow is used to
produce single droplets. Well controlled production of single
micro-droplets is necessary for studying accumulation of nano-
particles at the interface, the main target of the project. The
experiments performed indicated that small droplets (1um) are
created as satellites during fluid-threads break-up. The process of
a micro-thread formation was previously observed and
investigated [Kowalewski, Fluid Dyn. Res. 1996] for break-up of
viscous jets in air. Similar process is found in the present study
for two-liquids system. A hydrodynamic separation of small
satellites created after the thread break-up is perhaps the
simplest method of utilizing jet break-up for micro-droplets
production.
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