Experimental research on breakup of 2D power law liquid film

doi:10.1016/j.cjche.2015.03.011

Abstract

Abstract: On account of limited knowledge of the breakup of power law liquid film, the process of its disintegration and atomization was studied by using a planar liquid film. A linear stability analysis was adopted to predict the breakup characteristics of the power law film. The predicting formulas of stripping breakup length and diameter of ligament were put forward presently. Through high-speed photography and laser light sheet illumination, different breakup characteristics of flat power law film under different conditions were derived. The characteristic dimension of breakup regimes were defined and extracted. The effects of several parameters (injection pressure, ambient pressure, nozzle structure and fluid property) on the stripping breakup length and spray angle were investigated. The results revealed that increasing both the velocity of liquid film and the ambient pressure facilitated the breakup of film, reduced the stripping breakup length and enlarged the spray angle in different extents. The comparison between theoretical and experimental results was conducted to validate the feasibility of the linear stability theory.

Key words: Power law non-Newtonian fluid film, Liquid film disintegration, Two-phase flow, Stripping breakup length, Linear stability analysis

摘要： On account of limited knowledge of the breakup of power law liquid film, the process of its disintegration and atomization was studied by using a planar liquid film. A linear stability analysis was adopted to predict the breakup characteristics of the power law film. The predicting formulas of stripping breakup length and diameter of ligament were put forward presently. Through high-speed photography and laser light sheet illumination, different breakup characteristics of flat power law film under different conditions were derived. The characteristic dimension of breakup regimes were defined and extracted. The effects of several parameters (injection pressure, ambient pressure, nozzle structure and fluid property) on the stripping breakup length and spray angle were investigated. The results revealed that increasing both the velocity of liquid film and the ambient pressure facilitated the breakup of film, reduced the stripping breakup length and enlarged the spray angle in different extents. The comparison between theoretical and experimental results was conducted to validate the feasibility of the linear stability theory.

关键词: Power law non-Newtonian fluid film, Liquid film disintegration, Two-phase flow, Stripping breakup length, Linear stability analysis

Lixing Xu, Zhenyan Xia, Mengzheng Zhang, Qing Du, Fuqiang Bai. Experimental research on breakup of 2D power law liquid film[J]. , 2015, 23(9): 1429-1439.

References

[1] L. Rayleigh, On the instability of jets, Proc. Lond. Math. Soc. 10 (1878) 4-13.
[2] C. Weber, Zum Zerfall eines Flüssigkeits strahles, J. Appl. Math. Mech. (Z. Angew. Math. Mech.) 11 (1931) 136-154.
[3] R.P. Fraser, N. Dombrowski, J.H. Routley, The atomization of a liquid sheet by an impinging air stream, Chem. Eng. Sci. 18 (1963) 339-353.
[4] G.D. Crapper, N. Dombrowski, W.P. Jepson, G.A.D. Pyott, A note of the growth of Kelvin-Helmholtz waves on thin liquid sheets, J. Fluid Mech. 57 (1973) 671-672.
[5] H.B. Squire, Investigation on the instability of a moving liquid film, Br. J. Appl. Phys. 4 (1953) 167-169.
[6] X. Li, Mechanism of atomization of a liquid jet, ASME P. Des. 66 (1995) 113-120.
[7] M.C. Yuen, Non-linear capillary instability of a liquid jet, J. Fluid Mech. 33 (1968) 151-163.
[8] R.D. Reitz, F.V. Bracco, Mechanism of atomization of a liquid jet, Phys. Fluids 25 (1982) 1730-1742.
[9] X. Li, R.S. Tankin, On the temporal instability of a two-dimensional viscous liquid sheet, J. Fluid Mech. 226 (1991) 425-443.
[10] J. Shen, X. Li, Instability of an annular viscous liquid jet, Acta Mech. 114 (1996) 167-183.
[11] Q. Du, X. Li, Effect of gas stream swirls on the instability of viscous annular liquid jets, Acta Mech. 176 (2005) 61-81.
[12] Q. Du, N. Liu, J. Yin, The study on the relationship between breakup modes and gas- liquid interfaces, Chin. Sci. Bull. 53 (2008) 2898-2906.
[13] N. Ashgriz, Handbook of Atomization and Sprays, vol. 1, Springer Science+Business Media, 2011. 75-86.
[14] C. Hwang, J. Chen, J. Wang, J. Lin, Linear stability of power law liquid film flows down an inclined plane, J. Phys. D. Appl. Phys. 27 (1994) 2297-2301.
[15] Z. Gao, Instability of non-Newtonian jets with a surface tension gradient, J. Phys. A Math. Theor. 42 (2009) 65501.
[16] S.P. Lin, Z.W. Lian, Mechanisms of the breakup of liquid jets, AIAA J. 28 (1990) 120-126.
[17] A.L. Yarin, Free liquid jets and films: hydrodynamics and rheology, J. Fluid Mech. 312 (1993) 408-409.
[18] G. Brenn, Z. Liu, F. Durst, Linear analysis of the temporal instability of axisymmetrical non-Newtonian liquid jets, Int. J. Multiphase Flow 26 (2000) 1621-1644.
[19] Z. Liu, Z. Liu, Instability of a viscoelastic liquid jetwith axisymmetric and asymmetric disturbances, Int. J. Multiphase Flow 34 (2008) 42-60.
[20] W.Witherspoon, R.N. Parthasarathy, Breakup of viscous liquid sheets subjected to symmetric and asymmetric gas flow, J. Energy Res. Technol. 119 (1997) 184-192.
[21] Q. Chang, Instability analysis of a power law liquid jet, J. Fluid Mech. 198 (2013) 10-17.
[22] L.J. Yang, Linear instability analysis of planar non-Newtonian liquid sheets in two gas streams of unequal velocities, J. Fluid Mech. 167-168 (2012) 50-58.
[23] H.H. Jin, Large eddy simulation of flow field near nozzle of rectangular jet, J. Chem. Ind. Eng. (China) 55 (2004) 1243-1248 (in Chinese).
[24] J.E. Beck, A.H. Lefebvre, T.R. Koblish, Airblast atomization at conditions of low air velocity, J. Propuls. 25 (1991) 207-212.
[25] J.L. York, H.F. Stubbs, M.R. Tek, The mechanism of disintegration of liquid sheets, ASME Trans. 75 (1953) 1279-1286.
[26] F.W. Kroesser, S. Middleman, Viscoelastic jet stability, AIChE J. 15 (3) (1969) 383-391.
[27] A. Sarchami, N. Ashgriz, H.N. Tran, An atomization model for splash plate nozzles, AIChE J. 56 (4) (2009) 849-857.
[28] L.J. Qian, Simulation of droplet-gas flow in the effervescent atomization spray with an impinging plate, Chin. J. Chem. Eng. 17 (2009) 8-19.