Alfonso M. Gañán-Calvo, In collaboration with Miguel A. Herrada, Antonio Ojeda-Monge, Benjamin Bluth, Pascual Riesco-Chueca

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1 Afonso M. Gañán-Cavo, In coaboration with Migue A. Herrada, Antonio Ojeda-Monge, Benjamin Buth, Pascua Riesco-Chueca ESI, Dept. Aerospace Engineering and Fuid Mechanics University of Sevie, Spain. IPPT PAN Seminars. Warsaw, January 008

2 Focusing fuid r z D 1 D Focused fuid H L V IPPT PAN Seminars. Warsaw, January 008

3 Gañán-Cavo 1997, W ES Ganan-Cavo et a. 007 Nature Phys. 3, We may wish to contro these structures & make them as sma as possibe IPPT PAN Seminars. Warsaw, January 008

4 We seek for the geometrica and operationa conditions where the smaest possibe, monodisperse dropets are generated at a productivity of practica use IPPT PAN Seminars. Warsaw, January 008

5 T g C O T φ P a j θ D t D i θ θ t H D S Parameter ranges in experiments (G-C et a.): IPPT PAN Seminars. Warsaw, January 008

6 The sma yied per orifice has ed to the design of muti-orifice devices: 1.5 mm IPPT PAN Seminars. Warsaw, January 008

7 3D (axisymmetric) Fow focusing in siicon

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9 Ranges of pressure drop and fow rate: FF FB ΔP, bar , ul/min Re >> 1 1 8ρ Δ p ( ) gas ρv 4 π d *A. M. Gañán-Cavo. Phys. Rev. Letter, 80, 85, j d j 1/ 4 8 ρ π Δp 1/ (Bernoui) d o 1/ 4 8 ρ = π Δp Characteristic ength 1/ 4

10 Based on previous characteristic dimension, four main parameters inform on the roe payed by surface tension, viscosity and geometry (orifice size and tube-orifice distance) (1) We 4 1/ 3 4 3/ O p Δ = ρ π 4 1/ 3 4 1/ R Δ p ρ viscosity and geometry (orifice size and tube orifice distance) (1) 8 We 4 O = σ 4 Re = p μ ρ π 4 / 1 4 1/ 4 4 1/ 8 Δ = p D G ρ π D H G H / = Various geometries:

11 Roe payed by G H = H / D H

12 Water,60 Ethano,40 d50/do 1 0,1 GSD,0,00 1, ,60 1,40 1,0 0, , We We Fow Focusing Fow Burring

13 Roe payed by and

14 10 Water Ethano,0,00 cff tff ,80 d50/do GSD 1,60 0,1 1,40 1,0 0, , We We We 0

15 10, , ,80 d50/do Water Ethano GSD 1,60 0,1 1,40 1,0 0, , We We Why some iquids (water) exhibit arger sizes than predicted, in some (most) conditions? Why some conditions exhibit extremey good monodispersity (without externa excitation)? What exacty sets the minimum fow rate: C/A instabiity of the jet? Cone-jet fow transition? Is the dripping mode so bad?

16 Some recents FF numerica simuations: Liquid-iquid configuration for the production of microemusions: Michae M. Dupin et a. Physica Review E,73, 006. Microbubbing: M. J. Jensen et a. Physics of Fuids, 18, 006.

17 Geometrica configuration is fixed: g R 1 /R = , R /R = 1.75, R 3 /R = 3.5, L/R = H/R = 1 Characteristic magnitudes: * R * V= g /(π R ) IPPT PAN Seminars. Warsaw, January 008

18 ρ g * α =, ρ μg * β = μ, densities ratio viscosities ratio ρgv R *We =, Weber (gas) σ ρg * Re = VR, Reynods(gas) μ * ReR = * = g g ρu R, Reynods(tube) μ, Fow rates ratio Water-air experiments: Case 1 α = β = Case Re = Re = We = 8.13 We = 3.55 In these cases, we have studied the effect of changing in: 1. Meniscus-jet shape.. Minimum fow rate * for stabe jet. 3. Fow structure inside the meniscus. IPPT PAN Seminars. Warsaw, January 008

19 -VOF scheme: a) Expicit time advance b) CICSAM reconstruction *Commercia code used: FLUENT 6.3 Basic mesh: Δ z = Δ r = 0.0 Refined mesh: Δ z = Δ r = IPPT PAN Seminars. Warsaw, January 008

20 Case 1 =0.004 θ d in d out IPPT PAN Seminars. Warsaw, January 008

21 Case 1 Case * (minimum) * (minimum) IPPT PAN Seminars. Warsaw, January 008

22 Case 1 Case Diameters Contact anges IPPT PAN Seminars. Warsaw, January 008

23 Re >>1 1 Δp( gas ) 1 8ρ π d ρv 4 j (*) d j 8ρ π Δ p 1/ 4 1/

24 Case 1 Case = =

25 Case 1 = Case = High periodicity near the exit orifice (but not necessariy outside)

26 water (from syringe pump) (Coe-Pamer Series) with a 0 m syringe jetting dripping Auminium box 370 mm OD, 150 mm ID stainess stee capiary Air (pressure gauge) Two cameras to verify aignment Variabe distance H PMMA window 4 mm stainess stee disk 75 μm thick 00 μm orifice

27 We W 5 H=0,00mm Up Pressure increasing H=0,00mm Down H=0,150mm Up 4 H=0,150mm Down Jetting H=0,100mm Up H=0,100mm Down 3 H=0,075mm Up H=0,075mm Down H=0,050mm Up H=0,050mm Down C/A transition 1 0 Dripping Re jetting dripping Optimum distance H: H/D~0.5

28 DRIPPING JETTING

29 Case 1 Case Experimenta observations of recircuation ces: Co-fowing systems: S. L. Anna and H. C. Mayer, Phys. Fuids, 18, 1151 (006). R. Suryo, O. A. Basaran, Phys. Fuids, 18, 0810 (006) Tayor cones: Barrero et a. Phys. Rev. E, 58, (1998)

30 Sadde (max. pressure)

31 r r Sadde (max. pressure) ( ) 1/ 1/ / / ~ s R s U U R δ ρ μ δ = 1 Re ) /( ~ ) /( ~ / = = μ ρ ρ μ δ g g s g R r R U ~ O(1) S r R B μ = R r r R r C C R S s S Re / ) / ( ~ 1 = = μ ρ O(1) ρ B

32 s r = C 1 C Re R

33 300 Artices per year Subject: Fow Focusing (Source: Scopus) Gañán-Cavo [1] pioneered the use of a technique now caed fow-focusing where he used a co-fowing acceerating gas stream to reduce the radius of a iquid jet issuing out of a nozze.[3] He showed that a neary monodisperse spray is produced when the Weber number, which characterizes the reative importance of inertia force in the gas phase to the surface tension force, ies beow a critica vaue. Suryo, R. & Basaran O. A. (006) Phys. Fuids 18, 0810 IPPT PAN Seminars. Warsaw, January 008

34 Most work (experimenta) has been devoted to iquid-iquid FF in microfuidics ( panar FF) Anna, S.L., Bontoux, N., Stone, H.A. (003), App. Phys. Lett. 85, 364 (cited by 199) or gas in iquid FF (microbubbes) in microfuidics Ganan-Cavo, A.M., Gordio, J.M., (001), Phys. Rev. Lett. 87, (cited by 89) Garstecki, P., Gitin, I., Diuzio, W., Whitesides, G.M., Kumacheva, E., Stone, H.A. (004), App. Phys. Lett. 85, 649 (cited by 66) IPPT PAN Seminars. Warsaw, January 008

35 however, the origina iquid-in-gas configuration has been subject of smaer attention: Ganan-Cavo, A.M. (1998), Phys. Rev. Lett. 80, 85 (cited by 69) Amagro, B., Gañán-Cavo, A.M., Canas, A. (004), J. Ana. Atom. Spectrom., 19, 1346 (cited by 5) Arumuganathar, S., Irvine, S., McEwan, J.R., Jayasinghe, S.N. (008), J. App. Poymer Sci. 107, 115 IPPT PAN Seminars. Warsaw, January 008

36 IPPT PAN Seminars. Warsaw, January 008