Abstract
Instability and breakup of a viscous annular liquid sheet that is exposed to co-flowing inner and outer gas streams have been investigated using a nonlinear spatial stability analysis. A perturbation expansion method is used with the initial amplitude of the disturbance as the perturbation parameter. The evolution of the two gas–liquid interfaces is tracked until the sheet breaks up and the breakup length is determined. The model is validated by comparison with available experimental data. The effects of liquid swirl strength, gas-to-liquid density ratio, radius of curvature ratio, and liquid viscosity on the sheet instability and breakup have been studied. The results show that at very low values of liquid swirl, it has a stabilizing effect on sheet breakup, but as the swirl strength increases, it strongly destabilizes the sheet. Also, with increasing swirl strength, the occurrence of the large surface deformations moves from the inner interface to the outer interface. The sheet breakup length increases slightly and then decreases rapidly with an increase in liquid swirl strength. Without liquid swirl, the axisymmetric mode is the dominant instability mode. However, with increasing liquid swirl strength, the higher helical modes become dominant and the breakup becomes increasingly asymmetric. When the undisturbed liquid sheet has a purely axial motion, the inner gas stream is more effective in sheet breakup than the outer gas stream. In the presence of liquid swirl, the outer gas stream is more disruptive than the inner gas stream. The breakup length becomes shorter as gas-to-liquid density ratio and the radius of curvature ratio increases. Increase in liquid viscosity tends to slow the disturbance growth and increases the sheet breakup length.
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Abbreviations
- A :
-
Liquid swirl velocity
- a :
-
Unperturbed liquid jet inner radius
- A h :
-
Dimensionless unperturbed liquid jet inner radius
- b :
-
Unperturbed liquid jet outer radius
- B h :
-
Dimensionless unperturbed liquid jet outer radius
- E :
-
Dimensionless liquid swirl strength
- h :
-
Liquid sheet thickness
- i :
-
Imaginary unit
- k r :
-
Dimensionless wave number
- k i :
-
Dimensionless growth rate of disturbance
- p :
-
Pressure
- p′:
-
Pressure perturbation
- Q i :
-
Inner gas-to-liquid density ratio
- Q o :
-
Outer gas-to-liquid density ratio
- r :
-
Radial coordinate
- r i :
-
Dimensionless perturbed liquid sheet inner radius
- r o :
-
Dimensionless perturbed liquid sheet outer radius
- Re :
-
Liquid Reynolds number
- t :
-
Time
- u :
-
Axial velocity
- u′:
-
Axial velocity perturbation
- U :
-
Dimensionless axial velocity
- υ :
-
Radial velocity
- υ′:
-
Radial velocity perturbation
- w :
-
Azimuthal velocity
- w′:
-
Azimuthal velocity perturbation
- W i :
-
Inner gas-to-liquid velocity ratio
- W o :
-
Outer gas-to-liquid velocity ratio
- We :
-
Liquid Weber number
- z :
-
Axial coordinate
- θ :
-
Azimuthal coordinate
- η :
-
Dimensionless amplitude of disturbance
- ν :
-
Liquid kinematic viscosity
- ρ :
-
Density
- σ :
-
Liquid surface tension
- ω i :
-
Dimensionless frequency of disturbance
- i :
-
Inner gas phase
- i:
-
Imaginary part of a complex number
- l :
-
Liquid phase
- m :
-
Azimuthal wave number
- o :
-
Outer gas phase
- r :
-
Radial orientation
- r:
-
Real part of a complex number
- θ :
-
Azimuthal orientation
- z :
-
Axial orientation
- 0:
-
Initial (unperturbed)
- 1:
-
First order
- 2:
-
Second order
- 21:
-
First part of second order
- 22:
-
Second part of second order
References
Lefebvre A.H.: Airblast Atomization. Prog. Energy Comb. Sci 6, 233–261 (1980)
Lefebvre A.H.: Gas Turbine Combustion. Hemisphere, Washington, DC (1983)
Lefebvre A.H.: Atomization and Sprays. Hemisphere Publishing, Washington, DC (1989)
Sirignano W.A., Mehring C.: Review of theory of distortion and disintegration of liquid streams. Prog. Energy Comb. Sci 26, 609–655 (2000)
Lasheras J.C., Hopfinger E.J.: Liquid jet instability and atomization in a coaxial gas stream. Annu. Rev. Fluid Mech. 3, 275–308 (2000)
Yoon S.S., Heister S.D.: Categorizing linear theories for atomizing jets. At. Sprays 13, 499–516 (2003)
Lin, S. P.: Breakup of Liquid Sheets and Jets. Cambridge University Press, Cambridge (2003)
Ponstein J.: Instability of rotating cylindrical jets. Appl. Sci. Res. A 8, 425 (1959)
Schmidt D.P., Chiapetta L.M., Goldin G.M., Madabushi R.K.: Transient multi-dimensional modeling of air-blast atomizers. At. Sprays 13, 373–394 (2003)
Blaisot J.B., Adeline S.: Determination of the growth rate of instability of low velocity free falling jets. Exp. Fluids 29, 247–256 (2000)
Blaisot J.B., Adeline S.: Instabilities on a free falling jet under an internal flow breakup mode regime. Int. J. Multiph. Flow 29, 629–653 (2003)
Adzic M., Carvalho I.S., Heitor M.V.: Visualization of the disintegration on an annular liquid sheet in a coaxial airblast injector at low atomizing air velocities. Opt. Diagn. Eng. 5, 27–38 (2001)
Gaster M.: A note on the relation between temporally-increasing and spatially-increasing disturbances in hydrodynamic stability. J. Fluid Mech. 14, 222–224 (1964)
Chuech S.G.: Spatial instability of a viscous liquid sheet. Int. J. Numer. Meth. Fluids 50, 1461–1474 (2006)
Mehring C., Sirignano W.A.: Axisymmetric capillary waves on thin annular liquid sheets: II spatial development. Phys. Fluids 12(6), 1440–1460 (2000)
Panchagnula, M.V., Sojka, P.E., Bajaj, A.K.: The non-linear breakup of annular liquid sheets. In: Proceedings of the 11th Annual Conference Liquid Atom. Spray Systems, pp. 170–174 (1998)
Tharakan T.J., Ramamurthi K., Balakrishnan M.: Non-linear breakup of thin liquid sheets. Acta Mech. 156, 29–46 (2002)
Ibrahim A.A., Jog M.A.: Nonlinear instability of an annular liquid sheet exposed to gas flow. Int. J. Multiph. Flow 34, 647–664 (2008)
Lee C.P., Wang T.G.: A theoretical model for annular jet instability. Phys. Fluids 29, 2076–2085 (1986)
Ramos J.I.: Fluid dynamics of slender, thin, annular liquid jets. Int. J. Numer. Methods Fluids 21, 735–761 (1995)
Shen J., Li X.: Instability of an annular viscous liquid jet. Acta Mech. 114, 167–183 (1996)
Panchagnula, M.V., Sojka, P.E., Santangelo, P.J.: On the three-dimensional instability of a swirling, annular, inviscid liquid sheet subject to unequal gas velocities. Phys. Fluids 8, 3300–3312 (1996)
Alleborn N., Raszillier H., Durst F.: Linear stability of non-Newtonian annular liquid sheets. Acta Mech. 137, 33–42 (1998)
Liao Y., Jeng S.M., Jog M.A., Benjamin M.A.: A comprehensive model to predict simplex atomizer performance. J. Eng. Gas Turbines Power 121, 285–294 (1999)
Jeandel X., Dumouchel C.: Influence of the viscosity on the linear stability of an annular liquid sheet. Int. J. Heat Fluid Flow 20, 499–506 (1999)
Liao Y., Jeng S.M., Jog M.A., Benjamin M.A.: Instability of an annular liquid sheet surrounded by swirling airstreams. AIAA J. 38, 453–460 (2000)
Liao Y., Jeng S.M., Jog M.A., Benjamin M.A.: Advanced sub-model for airblast atomizers. J. Propuls. Power 17, 411–417 (2001)
Cao J.: Theoretical and experimental study of atomization from an annular liquid sheet. J. Automob. Eng. 217, 735–734 (2003)
Chen F., Tsaur J.-Y., Durst F., Das S.K.: On the axisymmetry of annular jet instabilities. J. Fluid Mech. 488, 355–367 (2003)
Du Q., Li X.: Effect of gas stream swirls on the instability of viscous annular liquid jets. Acta Mech. 176, 61–81 (2005)
Ibrahim A.A., Jog M.A., Jeng S.M.: Effect of liquid swirl velocity profile on the instability of a swirling annular liquid sheet. At. Sprays 16, 237–263 (2006)
Ibrahim A.A., Jog M.A.: Effect of liquid and air swirl strength and relative rotational direction on the instability of annular liquid sheet. Acta Mech. 186, 113–133 (2006)
Herrero E.P., MartinDel Valle E.M., Galan M.A.: Instability study of a swirling annular liquid sheet of polymer produced by air-blast atomization. Chem. Eng. J. 133, 69–77 (2007)
Mehring C., Sirignano W.A.: Axisymmetric capillary waves on thin annular liquid sheets part I: temporal stability. Phys. Fluids 12, 1417–1439 (2000)
Mehring C., Sirignano W.A.: Non-linear capillary waves on swirling, axisymmetric free liquid films. Int. J. Multiph. Flow 27, 1707–1734 (2001)
Mitra, S.K.: Breakup process of plane liquid sheets and prediction of initial droplet size and velocity distributions in sprays. Ph.D. thesis, University of Waterloo, Waterloo, Ontario (2001), http://uwspace.uwaterloo.ca/handle/10012/931
Shen, J.: Formation and Characteristics of Sprays from Annular Viscous Liquid Jet Breakup. PhD. Thesis, University of Victoria, Victoria, BC, Canada (1997)
Lin S.P., Kang D.J.: Atomization of a liquid jet. Phys. Fluids 30, 2000–2006 (1987)
Liao Y., Jeng S.M., Jog M.A., Benjamin M.A.: Effect of air swirl profile on the instability of a viscous liquid jet. J. Fluid Mech. 424, 1–20 (2000)
Dombrowski N., Hooper P.C.: The effect of ambient density on drop formation in sprays. Chem. Eng. Sci 17, 291–305 (1962)
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Yan, K., Jog, M.A. & Ning, Z. Nonlinear spatial instability of an annular swirling viscous liquid sheet. Acta Mech 224, 3071–3090 (2013). https://doi.org/10.1007/s00707-013-0896-0
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DOI: https://doi.org/10.1007/s00707-013-0896-0