Skip to main content
SpringerLink
Log in

Acoustically excited air-assisted liquid sheets

  • Original
  • Published:
Experiments in Fluids Aims and scope Submit manuscript

Abstract

The effect of acoustic excitation on the disintegration characteristics of air-assisted liquid sheets, which utilize water at ambient temperature, and for velocities up to 1.8 m/s, is investigated. The study using high-speed imaging techniques revealed that optimum frequency modulation of the perturbation generator has a pronounced influence on the associated surface waves and the subsequent breakup of the liquid sheet. The analysis includes characterization of critical wave amplitude, breakup length, and breakup frequency, for Weber numbers in the range 0.30<We abs<0.44, which are compared with flow features in the absence of acoustic excitation. The results show that acoustic perturbation can effectively suppress the dominance of gravitational and surface tension effects. As a consequence, for low Weber number flows, the interfacial waves exhibit regularity, and thus a better control of primary breakup processes of liquid sheet may be accomplished.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4a, b.
Fig. 5a, b.
Fig. 6a, b.
Fig. 7.
Fig. 8.
Fig. 9.

Similar content being viewed by others

Abbreviations

f b :

breakup frequency of the liquid sheet

f p :

acoustic excitation frequency

L b :

breakup length of the liquid sheet

p rms :

root-mean-square of pressure fluctuations

p rms o :

root-mean-square of pressure fluctuations at the acoustic source

Q a :

airflow rate at the nozzle outlet

Q l :

liquid flow rate at the nozzle outlet

t s :

initial liquid sheet thickness

U a :

mean air velocity at the nozzle outlet

U l :

liquid velocity at the nozzle outlet

U n :

component of air velocity normal to the liquid sheet axis (U a sin 30°)

U r :

relative velocity between air and liquid (U acos 30°−U l)

We abs :

absolute Weber number [(We r 2+We n 2)0.5]

We n :

Weber number based on normal air momentum (ρ a U n 2 t s/σ)

We r :

relative Weber number (ρ a U r 2 t s/σ)

ρ a :

density of air

σ :

surface tension of water at 20°C

η c :

critical wave amplitude

Δθ :

phase difference

References

  • Chigier N (1981) Energy combustion and the environment. McGraw-Hill, New York

  • Chung IP, Presser C, Dressler JL (1998) Effect of piezoelectric transducer modulation on liquid sheet disintegration. Atomization Sprays 8:479–502

    CAS  Google Scholar 

  • Crapper GD, Dombrowski N, Jepson WP, Pyott GA (1973) A note on the growth of Kelvin–Helmholtz waves on thin liquid sheets. J Fluid Mech 57:671–672

    Google Scholar 

  • Crapper GD, Dombrowski N (1984) A note on the effect of forced disturbances on the stability of thin liquid sheets and on the resulting drop size. Int J Multiphase Flow 10:731–736

    Article  CAS  Google Scholar 

  • Dombrowski N, Fraser RP (1954) A photographic investigation into the disintegration of liquid sheets. Philos Trans R Soc London A 247:101–130

    Google Scholar 

  • Dombrowski N, Johns WR (1963) The aerodynamic instability and disintegration of viscous liquid sheets. Chem Eng Sci 18:203–214

    Article  CAS  Google Scholar 

  • Fahy FJ (1995) Sound intensity, 2nd edn. Chapman and Hall, London

  • Fernandes EC, Heitor MV (1997) Simultaneous measurements of velocity, pressure, temperature and heat release in an oscillating flame. In: Ninetieth Symposium of Propulsion and Energetics on the Advanced Non-intrusive Instrumentation for Propulsion Engines, AGARD, Brussels, 20–24 October 1997

  • Hagerty W, Shea JF (1955) A study of stability of plane fluid sheets. J Appl Mech 22:509–514

    Google Scholar 

  • Kinsler LE, Frey AR, Coppens AB, Sanders JV (1982) Fundamentals of acoustics, 3rd edn. Wiley, New York

  • Lefebvre AH (1989) Atomization and sprays. Hemisphere, New York, pp 201–267

  • Lozano A, Barreras F (2001) Experimental study of the gas flow in an air-blasted liquid sheet. Exp Fluids 31:367–376

    Article  CAS  Google Scholar 

  • Mansour A, Chigier N (1990) Disintegration of liquid sheets. Phys Fluids A 2:706–719

    Article  CAS  Google Scholar 

  • Mansour A, Chigier N (1991) Dynamic behavior of liquid sheets. Phys Fluids A 3:2971–2980

    Article  CAS  Google Scholar 

  • McCarthy MJ, Molloy NA (1974) Review of stability of liquid jets and the influence of nozzle design. Chem Eng J 7:1–20

    Article  Google Scholar 

  • Santos D (1998) Liquid film disintegration. (In Portuguese.) MSc thesis, Technical University of Lisbon

  • Sivadas V, Heitor MV (2003) Surface waves of air-assisted liquid sheets. Atomization Sprays (in press)

  • Yakubenko PA (1997) Global capillary instability of an inclined jet. J Fluid Mech 346:181–200

    Article  CAS  Google Scholar 

  • Zhao FQ, Lai MC, Amer AA, Dressler JL (1996) Atomization characteristics of pressure modulated automotive port injector sprays. Atomization Sprays 6:461–483

    Google Scholar 

Download references

Acknowledgements

The authors acknowledge financial support from the Portuguese Science and Technology Foundation, project 34586/99, and the EC funded project DIME, "Direct Injection Spray Engine Processes—Mechanisms to Improve Performance", DIME ENK6-2000-00101. V. Sivadas is a post-doctoral research fellow at IST under the sponsorship of the Portuguese Science and Technology Foundation.

Author information

Authors and Affiliations

  1. Laboratory of Thermofluids, Combustion and Energy Systems Center for Innovation, Technology and Policy Research, IN+ Instituto Superior Técnico, Technical University of Lisbon, Av. Rovisco Pais, 1049-001, Lisbon, Portugal

    V. Sivadas, E. C. Fernandes & M. V. Heitor

Authors
  1. V. Sivadas
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. E. C. Fernandes
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. M. V. Heitor
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to V. Sivadas.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Sivadas, V., Fernandes, E.C. & Heitor, M.V. Acoustically excited air-assisted liquid sheets. Exp Fluids 34, 736–743 (2003). https://doi.org/10.1007/s00348-003-0618-9

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00348-003-0618-9

Keywords

Search

Navigation