Conex 2004

1
Polish Academy of Sciences Institute of
Fundamental Technological Research
Break-up of liquid jet in co-flow experimental
study
S. Blonski, P.Korczyk, T.A. Kowalewski
http//fluid.ippt.gov.pl/conex
2
MOTIVATION
Visualization of liquid jet break-up and droplet
formation for co-flow
Glycerol jet in air
3
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

Qe 1 - 5cm3/s
Qj 5 - 30mm3/s
Geometry for jet breakup observation channel
size 30 x 8 x 10 mm needle diameter 0.5 mm
4
EXPERIMENTAL SETUP
5
Liquid jet break-up visualization
Used geometry

• Used materials
• water-alcohol mixture (52) S50 silicone oil
  1wt SDS
• water-alcohol mixture (52) S500 silicone oil
  1wt SDS
• Used microscope lens 4x/NA0.13/WD17.1mm

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
6
Liquid jet break-up visualization
Qj 33 mm3/s Qe 1.08 cm3/s
Qj 22 mm3/s Qe 1.08 cm3/s Break-up period 60
ms
Silicone oil jet S50 Image width corresponds to
3.6mm
7
Liquid jet break-up visualization
3.6 mm
S50 oil water-alkohol SDS 500 fps Qj 22
mm3/s Qe 1.1 cm3/s
8
Liquid jet break-up visualization
3.6 mm
S50 oil water-alkohol SDS 500 fps Qj 33
mm3/s Qe 1.1 cm3/s
9
Liquid jet break-up visualization
3.6 mm
S500 oil water-alkohol SDS 500 fps Qj 28
mm3/s Qe 1.3 cm3/s
10
Liquid jet break-up visualization
Disturbed jet
Long, cylindrical jet
Silicone oil jet S50 Qj 22 mm3/s Qe 2.7
cm3/s Image width corresponds to 3.6mm
11
Liquid jet break-up visualization
Filament shortly before droplet separation Qj
14 mm3/s Qe 1.47 cm3/s Break-up period 240 ms
Qj 33 mm3/s Qe 1.3 cm3/s Period of the
capillary wave 60 ms
Silicone oil jet S500 Image width corresponds to
3.6mm
12
Liquid jet break-up visualization
3.6 mm
S50 oil water-alcohol 1wt SDS 500 fps Qj
33 mm3/s Qe 2.7 cm3/s
13
Liquid jet break-up visualization
3.6 mm
S50 oil water-alcohol 1wt SDS 500 fps Qj
33 mm3/s Qe 5 cm3/s
14
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.