Microfluidics and Nanofluidics

, Volume 18, Issue 4, pp 599–612 | Cite as

Investigations on the characterization of laminar and transitional flow conditions after high pressure homogenization orifices

  • Katharina Kelemen
  • F. E. Crowther
  • C. Cierpka
  • L. L. Hecht
  • C. J. Kähler
  • H. P. Schuchmann
Research Paper

Abstract

High pressure homogenization is a well-established technique to achieve droplets in the submicron range. However, droplet breakup mechanisms are still not completely understood, since studies to characterize the flow are limited due to very small dimensions (typically several micrometers) and very large velocity ranges (from almost stagnant flow to 300 m/s and more). Furthermore, cavitation can occur resulting in multiphase flow. So far, experiments were performed only via integral measurements of, for example, the pressure drop or the droplet size distribution at the outlet. In the current study, this gap shall be closed using Particle Image Velocimetry measurements to analyze the flow field. In addition, an overall method, the characteristic correlation between the discharge coefficient (CD) and Re0.5 is used to distinguish between laminar, transitional and turbulent flow conditions at Reynolds numbers based on the channel width (d = 200 µm) between 250 and 22,500. The investigated orifices of this study had different positions of the constriction: coaxial and next to the wall. For both orifices, the CD measurement was applicable and showed different characteristic regions which can be associated with laminar, transitional and turbulent flow conditions. Mean velocity fields and fluctuations were measured quantitatively at the outlet and 50 diameters downstream using Micro Particle Image Velocimetry (µ-PIV) in an optically accessible orifice. Increased velocity fluctuations were found in the shear layers when the flow turns from laminar into unstable transitional conditions. The combination of both measurement techniques will help to optimize these systems for the future.

Keywords

High pressure homogenization Discharge coefficient Orifice µPIV 

List of Symbols

A [–]

Cross-sectional area of the orifice

B [mm]

Width of the squared orifice

B [mm]

Width of the squared inlet and outlet of the orifice unit

CD [–]

Discharge coefficient

CD,const [–]

Constant discharge coefficient

D [mm]

Diameter of the orifice

D [mm]

Diameter of the inlet and outlet of the orifice unit

d/D [–]

Ratio of orifice diameter to outlet diameter

h [mm]

Step height of a backward facing step

H [mm]

Outlet height of a backward facing step

L [mm]

Length of the orifice

Ntotal [–]

Number of images

NVector [–]

Number of vectors accounting for calculation

Δp [bar]

Homogenization pressure

Δp1 [bar]

Pressure loss after the first orifice unit

Δpideal [bar]

Frictionless pressure loss

Δpmax [bar]

Maximum pressure loss

Δpreal [bar]

Real pressure loss

Δptotal [bar]

Total homogenization pressure

Re [–]

Reynolds number

Δt [s]

Interframing time between two images

u [m/s]

Mean axial velocity

ub [m/s]

Mean bulk velocity

uexit,c [m/s]

Mean exit centerline velocity

um,c [m/s]

Mean centerline velocity

u2/um,c2 [–]

Normalized Reynolds shear stresses axial direction

v2/um,c2 [–]

Normalized Reynolds shear stresses radial direction

\(\dot{V}\) [m3/s]

Volume flow rate

x [mm]

Streamwise or axial coordinate

x/d or x/b resp.

Normalized distance after the orifice

y [mm]

Lateral or radial coordinate

y/d or y/b resp.

Normalized diameter of the orifice

z

Height coordinate

Greek letters

η [mPa s]

Dynamic viscosity of the fluid

ρ [kg/m3]

Density of the fluid

cp

Counter pressure

µ-PIV

Micro Particle Image Velocimetry

PEG

Polyethylene glycol

References

  1. Armaly BF, Durst F, Pereira JCF, Schönung B (1983) Experimental and theoretical investigation of backward-facing step flow. J Fluid Mech 127:473–496CrossRefGoogle Scholar
  2. Ball CG, Fellouah H, Pollard A (2012) The flow field in turbulent round free jets. Prog Aerosp Sci 50:1–26CrossRefGoogle Scholar
  3. Blonski S, Korczyk PM, Kowalewski TA (2007) Analysis of turbulence in a micro-channel emulsifier. Int J Therm Sci 46(11):1126–1141CrossRefGoogle Scholar
  4. Bogema M, Monkmeyer PL (1960) The quadrant edge orifice—a fluid meter for low Reynolds numbers. J Basic Eng 82:729–734CrossRefGoogle Scholar
  5. Brennen CE (1995) Cavitation and bubble dynamics, Oxford University Press, 0-19-509409-3Google Scholar
  6. Freudig B, Tesch S, Schubert H (2003) Production of emulsions in high-pressure homogenizers—Part II: influence of cavitation on droplet breakup. Eng Life Sci 6(3):266–270CrossRefGoogle Scholar
  7. Galinat S, Torres LG, Masbernat O, Guiraud P, Risso F, Dalmazzone C, Noik C (2007) Breakup of a drop in a liquid–liquid pipe flow through an orifice. AIChE J 53(1):56–68CrossRefGoogle Scholar
  8. Gothsch T, Schilcher C, Beinert S, Richter C, Dietzel A, Büttgenbach S, Kwade A (2014) High-pressure microfluidic system (HPMS): flow and cavitation measurements in supported silicon microsystem. Microfluid Nanofluidics. doi:10.1007/s10404-014-1419-6 Google Scholar
  9. Grace HP (1982) Dispersion phenomena in high viscosity immiscible fluid systems and application of static mixers as dispersion devices in such systems. Chem Eng Commun 14(3–6):225–277CrossRefGoogle Scholar
  10. Hinze JO (1955) Fundamentals of the hydrodynamic mechanism of splitting in dispersion processes. AIChE J 1(3):289–295CrossRefGoogle Scholar
  11. Hsiao FB, Lim YC, Huang JM (2010) On the near-field flow structure and mode behaviors for the right-angle and sharp-edged orifice plane jet. Exp Therm Fluid Sci 34(8):1282–1289CrossRefGoogle Scholar
  12. Innings F, Trägardh C (2007) Analysis of the flow field in a high-pressure homogenizer. Exp Therm Fluid Sci 32(2):345–354CrossRefGoogle Scholar
  13. Innings F, Fuchs L, Tragardh C (2011) Theoretical and experimental analyses of drop deformation and break-up in a scale model of a high-pressure homogenizer. J Food Eng 103(1):21–28CrossRefGoogle Scholar
  14. Johansen FC (1930) Flow through pipe orifices at low Reynolds numbers. Proc R Soc Lond A Math Phys Sci 126(801):231–245CrossRefMATHGoogle Scholar
  15. Karbstein H (1994) Untersuchungen zum Herstellen und Stabilisieren von Öl-in-Wasser-Emulsionen, Dissertation, Universität Karlsruhe (TH)Google Scholar
  16. Keane RD, Adrian RJ (1990) Optimization of particle image velocimeters. 1. Double pulsed systems. Meas Sci Technol 1(11):1202–1215CrossRefGoogle Scholar
  17. Kelemen K, Schuch A, Schuchmann HP (2014) Influence of flow conditions in high pressure orifices on droplet disruption of O/W emulsions. Chem Eng Technol 37(7):1227–1234Google Scholar
  18. Kolmogorov AN (1958) Über die Zerstäubung von Tropfen in einer turbulenten Strömung. In: Goering H (ed) Sammelband zur statistischen Theorie der Turbulenz. Akademie-Verlag, BerlinGoogle Scholar
  19. Lichtarowicz A, Duggins RK, Markland E (1965) Discharge coefficients for incompressible non-cavitating flow through long orifices. J Mech Eng Sci 7(2):210–219CrossRefGoogle Scholar
  20. Mi J, Nathan GJ (2010) Statistical properties of turbulent free jets issuing from nine differently-shaped nozzles. Flow Turbul Combust 84(4):583–606CrossRefMATHGoogle Scholar
  21. Mi J, Kalt P, Nathan GJ, Wong CY (2007) PIV measurements of a turbulent jet issuing from round sharp-edged plate. Exp Fluids 42(4):625–637CrossRefGoogle Scholar
  22. Milanovic IM, Hammad KJ (2010) PIV Study of the near-field region of a turbulent round jet, 3rd Joint US-European Fluids Engineering Summer Meeting and 8th International Conference on Nanochannels, Microchannels, and MinichannelsGoogle Scholar
  23. Olsen MG, Adrian RJ (2000) Out-of-focus effects on particle image visibility and correlation in microscopic particle image velocimetry. Exp Fluids 29:S166–S174CrossRefGoogle Scholar
  24. Pai S-I (1954) Fluid dynamics of jets. D. van Nostrand Company Inc, TorontoMATHGoogle Scholar
  25. Reynolds O (1883) An experimental investigation of the circumstances which determine whether the motion of water shall be direct or sinuous, and of the law of resistance in parallel channels. Philos Trans R Soc Lond 174:935–982CrossRefMATHGoogle Scholar
  26. Rossi M, Segura R, Cierpka C, Kahler CJ (2012) On the effect of particle image intensity and image preprocessing on the depth of correlation in micro-PIV. Exp Fluids 52(4):1063–1075CrossRefGoogle Scholar
  27. Santiago JG, Wereley ST, Meinhart CD, Beebe DJ, Adrian RJ (1998) A particle image velocimetry system for microfluidics. Exp Fluids 25(4):316–319CrossRefGoogle Scholar
  28. Schlichting H (1933) Laminare Strahlausbreitung. Z Angew Math Mech 13(4):260–263CrossRefMATHGoogle Scholar
  29. Singh G, Sundararajan T, Bhaskaran KA (2003) Mixing and entrainment characteristics of circular and noncircular confined jets. J Fluids Eng 125(5):835–842CrossRefGoogle Scholar
  30. Stang M, Schuchmann HP, Schubert H (2001) Emulsification in high-pressure homogenizers. Eng Life Sci 4(1):151–157CrossRefGoogle Scholar
  31. Tihon J, Penkavova V, Havlica J, Simcik M (2012) The transitional backward-facing step flow in a water channel with variable expansion geometry. Exp Therm Fluid Sci 40:112–125CrossRefGoogle Scholar
  32. Tollmien W (1926) Berechnung turbulenter Ausbreitungsvorgänge. Z Angew Math Mech 6(6):468–478CrossRefMATHGoogle Scholar
  33. Tunay T, Sahin B, Akilli H (2004) Investigation of laminar and turbulent flow through an orifice plate inserted in a pipe. Trans Can Soc Mech Eng 28(2B):403–414Google Scholar
  34. Vennemann P, Kiger KT, Lindken R, Groenendijk BCW, Stekelenburg-de Vos S, ten Hagen TLM, Ursem NTC, Poelmann RE, Westerweel J, Hierck BP (2006) In vivo micro particle image velocimetry measurements of blood-plasma in the embryonic avian heart. J Biomech 39(7):1191–1200CrossRefGoogle Scholar
  35. Wolf F, Schuch A, Köhler K, Schuchmann HP (2012) Ansatz zur Beschreibung der zerkleinerungsrelevanten Strömungsverhältnisse beim Emulgieren von W/O-Emulsionen mit Lochblenden. Chem Ing Tech 84(12):2215–2220. doi:10.1002/cite.201100065 CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Katharina Kelemen
    • 1
  • F. E. Crowther
    • 1
  • C. Cierpka
    • 2
  • L. L. Hecht
    • 1
  • C. J. Kähler
    • 2
  • H. P. Schuchmann
    • 1
  1. 1.Institute of Process Engineering in Life Sciences Section I: Food Process EngineeringKarlsruhe Institute of TechnologyKarlsruheGermany
  2. 2.Institute of Fluid Dynamics and AerodynamicsUniversität der Bundeswehr MünchenNeubibergGermany

Personalised recommendations