Experimental and Computational Multiphase Flow

, Volume 2, Issue 4, pp 199–211 | Cite as

A technical review of research progress on thin liquid film thickness measurement

  • Bo Wang
  • Bingzheng Ke
  • Bowen Chen
  • Ru Li
  • Ruifeng TianEmail author
Review Article


The thickness of the thin liquid film and its effects have always been a research hotspot in nuclear power applications and operating nuclear power plants, because the flow phenomenon of the liquid film is extremely common in multiphase flow research. Based on papers published in recent years, novel research progress on thin film thickness is reviewed from the following two perspectives: the experimental measurement and the theoretical model of liquid film thickness. For the experimental measurement, methods mainly include the PLIF method, the capacitance method, and the ultrasonic method. The following contents in this part are mainly reviewed from the PLIF method, the capacitance method, the ultrasonic method, and other methods for the measurement of the liquid film thickness on the wall, the liquid film thickness on the tube wall, and other aspects of the liquid film thickness. For the model, the theoretical model of liquid film thickness on the wall is mainly reviewed from two aspects: vertical flow and horizontal flow. Other models are mainly reviewed from the following aspects. They are annular film thickness, liquid film thickness for gas–liquid annular flow, and film thickness in pipes.


film thickness PLIF technology theoretical model experimental measurement capacitance method 



Archimedes number


Bond number based on the bubble acceleration


Capacitance between two parallel conductive plates


Capillary number


Criterion for the limit in capillary number


Outside diameter of tube


Tube inner diameter


Froude number for gas phase


Liquid film thickness


Sum of the reflected light intensity


Incident intensity


Spectral absorption coefficient


Refractive indexes of air absorption medium


Refractive indexes of liquid absorption medium


Reflectivity on the liquid-gas interface


Liquid film Reynolds number


Liquid feeding rate


Intertube spacing


Dimensionless slip velocity


Weber number


Weber number for liquid phase


Weber number for gas phase

Greek symbols


Modification coefficient


Dynamic viscosity


Incident angle


Circumferential angle measured from the top of the horizontal tube


Circumferential angle


Liquid flow rate on one side per unit length of cylinder


Flow rate of the liquid on one side of the tube


Density of the liquid


Density of liquid


Density of gas


Liquid film thickness


Initial liquid film thickness


Dielectric constant


Surface tension of the liquid


Disc spinning speed



Computational fluid dynamics


Diode laser absorption spectroscopy


Laser confocal displacement meter


Laser Doppler velocimeter


Laser focus displacement meter


Laser induced fluorescence


Planar laser induced fluorescence


Taylor analogy breakup


Turbulent fluidized bed


Thin film colorimetric interferometry


Water film thickness



Decelerated condition


Gas phase


Liquid phase


Steady condition



The authors would like to acknowledge the financial support provided by the Ph.D. Student Research and Innovation Fund of the Fundamental Research Funds for the Central Universities, the Fundamental Research Funds for the Central Universities, the National Natural Science Foundation of China (No. 51676052), and Chinese Universities Scientific Fund.


  1. Abdulkadir, M., Azzi, A., Zhao, D., Lowndes, I. S., Azzopardi, B. J. 2014. Liquid film thickness behaviour within a large diameter vertical 180° return bend. Chem Eng Sci, 107: 137–148.Google Scholar
  2. Abdulkadir, M., Samson, J. N., Zhao, D., Okhiria, D. U., Hernandez-Perez, V. 2018. Annular liquid film thickness prediction in a vertical 180° return bend. Exp Therm Fluid Sci, 96: 205–215.Google Scholar
  3. Åkesjö, A., Vamling, L., Sasic, S., Olausson, L., Innings, F., Gourdon, M. 2018. On the measuring of film thickness profiles and local heat transfer coefficients in falling films. Exp Therm Fluid Sci, 99: 287–296.Google Scholar
  4. Al-Aufi, Y. A., Hewakandamby, B. N., Dimitrakis, G., Holmes, M., Hasan, A., Watson, N. J. 2019. Thin film thickness measurements in two phase annular flows using ultrasonic pulse echo techniques. Flow Meas Instrum, 66: 67–78.Google Scholar
  5. Bai, D., Shibuya, E., Masuda, Y., Nishio, K., Nakagawa, N., Kato, K. 1995. Distinction between upward and downward flows in circulating fluidized beds. Powder Technol, 84: 75–81.Google Scholar
  6. Berna, C., Escrivá, A., Muñoz-Cobo, J. L., Herranz, L. E. 2014. Review of droplet entrainment in annular flow: Interfacial waves and onset of entrainment. Prog Nucl Energ, 74: 14–43.Google Scholar
  7. Bi, H.-T., Zhou, J., Qin, S.-Z., Grace, J. R. 1996. Annular wall layer thickness in circulating fluidized bed risers. Can J Chem Eng, 74: 811–814.Google Scholar
  8. Bonilla-Riaño, A., Rodriguez, I. H., Bannwart, A. C., Rodriguez, O. M. H. 2015. Film thickness measurement in oil–water pipe flow using image processing technique. Exp Therm Fluid Sci, 68: 330–338.Google Scholar
  9. Bonilla-Riaño, A., Velasco-Peña, H. F., Bannwart, A. C., Prasser, H. M., Rodriguez, O. M. H. 2019. Water film thickness measurement system for oil-water pipe flow. Flow Meas Instrum, 66: 86–98.Google Scholar
  10. Bretherton, F. P. 1961. The motion of long bubbles in tubes. J Fluid Mech, 10: 166–188.MathSciNetzbMATHGoogle Scholar
  11. Cen, H., Lugt, P. M. 2019. Film thickness in a grease lubricated ball bearing. Tribol Int, 134: 26–35.Google Scholar
  12. Chao, Q., Zhang, J.-H., Xu, B., Wang, Q. 2018. Multi-position measurement of oil film thickness within the slipper bearing in axial piston pumps. Measurement, 122: 66–72.Google Scholar
  13. Chen, B.-W., Li, J.-S., Mao, F., Tian, R.-F. 2019. Numerical study on the characteristics of single wetted flat wire with single droplet impact under the disturbance of airflow. Nucl Eng Des, 345: 74–84.Google Scholar
  14. Chen, B.-W., Tian, R.-F., Mao, F. 2020. Analysis of special phenomena of droplet impact on horizontal liquid film at low velocity. Ann Nucl Energy, 136: 107038.Google Scholar
  15. Chen, X., Shen, S., Wang, Y., Chen, J., Zhang, J. 2015. Measurement on falling film thickness distribution around horizontal tube with laser-induced fluorescence technology. Int J Heat Mass Tran, 89: 707–713.Google Scholar
  16. Cheng, Y.-S., Deng, K.-Y., Li, T. 2010. Measurement and simulation of wall-wetted fuel film thickness. Int J Therm Sci, 49: 733–739.Google Scholar
  17. Conte, G., Azzopardi, B. J. 2003. Film thickness variation about a T-junction. Int J Multiphase Flow, 29: 305–328.zbMATHGoogle Scholar
  18. Donniacuo, A., Charnay, R., Mastrullo, R., Mauro, A. W., Revellin, R. 2015. Film thickness measurements for annular flow in minichannels: Description of the optical technique and experimental results. Exp Therm Fluid Sci, 69: 73–85.Google Scholar
  19. Drosos, E. I. P., Paras, S. V., Karabelas, A. J. 2004. Characteristics of developing free falling films at intermediate Reynolds and high Kapitza numbers. Int J Multiphase Flow, 30: 853–876.zbMATHGoogle Scholar
  20. Estrada-Pérez, C. E., Hassan, Y. A., Tan, S.-C. 2011. Experimental characterization of temperature sensitive dyes for laser induced fluorescence thermometry. Rev Sci Instrum, 82: 074901.Google Scholar
  21. Fairbrother, F., Stubbs, A. E. 1935. 119. Studies in electro-endosmosis. Part VI. The “bubble-tube” method of measurement. J Chem Soc: 527–529.Google Scholar
  22. Fryza, J., Sperka, P., Krupka, I., Hartl, M. 2018. Effects of lateral harmonic vibrations on film thickness in EHL point contacts. Tribol Int, 117: 236–249.Google Scholar
  23. Fu, Q.-F, Yang, L.-J, Qu, Y.-Y. 2011. Measurement of annular liquid film thickness in an open-end swirl injector. Aerospace Sci Technol, 15: 117–124.Google Scholar
  24. Fukano, T., Furukawa, T. 1998. Prediction of the effects of liquid viscosity on interfacial shear stress and frictional pressure drop in vertical upward gas–liquid annular flow. Int J Multiphase Flow, 24: 587–603.zbMATHGoogle Scholar
  25. Ghiaasiaan, S. M., Wu, X., Sadowski, D. L., Abdel-Khalik, S. I. 1997. Hydrodynamic characteristics of counter-current two-phase flow in vertical and inclined channels: Effects of liquid properties. Int J Multiphase Flow, 23: 1063–1083.zbMATHGoogle Scholar
  26. Han, Y. B., Shikazono, N. 2009. Measurement of liquid film thickness in micro square channel. Int J Multiphase Flow, 35: 896–903.Google Scholar
  27. Han, Y. B., Shikazono, N. 2010. The effect of bubble acceleration on the liquid film thickness in micro tubes. Int J Heat Fluid Fl, 31: 630–639.Google Scholar
  28. Han, Y., Kanno, H., Ahn, Y. J., Shikazono, N. 2015. Measurement of liquid film thickness in micro tube annular flow. Int J Multiphase Flow, 73: 264–274.Google Scholar
  29. Han, Y., Shikazono, N. 2009. Measurement of the liquid film thickness in micro tube slug flow. Int J Heat Fluid Fl, 30: 842–853.Google Scholar
  30. Harris, A. T., Thorpe, R. B., Davidson, J. F. 2002. Characterisation of the annular film thickness in circulating fluidised-bed risers. Chem Eng Sci, 57: 2579–2587.Google Scholar
  31. Henstock, W. H., Hanratty, T. J. 1976. The interfacial drag and the height of the wall layer in annular flows. AIChE J, 22: 990–1000.Google Scholar
  32. Hori, K., Nakasatomi, M., Nishikawa, K., Sekoguchi, K. 1978. On ripple of annular two-phase flow: 3rd report. effect of liquid viscosity on characteristics of wave and interfacial friction factor. Transactions of the Japan Society of Mechanical Engineers, 44: 3847–3856.Google Scholar
  33. Hou, H., Bi, Q., Ma, H., Wu, G. 2012. Distribution characteristics of falling film thickness around a horizontal tube. Desalination, 285: 393–398.Google Scholar
  34. Ishii, M., Grolmes, M. A. 1975. Inception criteria for droplet entrainment in two-phase concurrent film flow. AIChE J, 21: 308–318.Google Scholar
  35. Jablonka, K., Glovnea, R., Bongaerts, J. 2018. Quantitative measurements of film thickness in a radially loaded deep-groove ball bearing. Tribol Int, 119: 239–249.Google Scholar
  36. Ju, P., Liu, Y., Ishii, M., Hibiki, T. 2018a. Prediction of rod film thickness of vertical upward co-current adiabatic flow in rod bundle. Ann Nucl Energy, 121: 1–10.Google Scholar
  37. Ju, P., Yang, X., Schlegel, J. P., Liu, Y., Hibiki, T., Ishii, M. 2018b. Average liquid film thickness of annular air-water two-phase flow in 8×8 rod bundle. Int J Heat Fluid Fl, 73: 63–73.Google Scholar
  38. Kim, M.-G., Choi, G. 2019. Accurate determination of two-dimensional thin film thickness in spectroscopic imaging reflectometer using color camera and tunable aperture. Opt Commun, 435: 75–80.Google Scholar
  39. Kim, S. W., Kirbas, G., Bi, H., Lim, C., Grace, J. R. 2004. Flow structure and thickness of annular downflow layer in a circulating fluidized bed riser. Powder Technol, 142: 48–58.Google Scholar
  40. Lewis, J. M., Wang, Y. 2018. Two-phase frictional pressure drop and water film thickness in a thin hydrophilic microchannel. Int J Heat Mass Tran, 127: 813–828.Google Scholar
  41. Li, L.-G., Zhao, Z.-W., Zhu, J., Kwan, A. K. H., Zeng, K. L. 2018. Combined effects of water film thickness and polypropylene fibre length on fresh properties of mortar. Constr Build Mater, 174: 586–593.Google Scholar
  42. Li, Y.-Z., Li, T., Zhang, H.-T., Sun, Q., Ying, W. 2017. LDV measurements of particle velocity distribution and annular film thickness in a turbulent fluidized bed. Powder Technol, 305: 578–590.Google Scholar
  43. Luo, D., Ghiaasiaan, S. M. 1997. Liquid-side interphase mass transfer in cocurrent vertical two-phase channel flows. Int J Heat Mass Tran, 40: 641–655.Google Scholar
  44. Mac Giolla Eain, M., Egan, V., Punch, J. 2013. Film thickness measurements in liquid–liquid slug flow regimes. Int J Heat Fluid Fl, 44: 515–523.Google Scholar
  45. Mantripragada, V. T., Sarkar, S. 2017. Prediction of drop size from liquid film thickness during rotary disc atomization process. Chem Eng Sci, 158: 227–233.Google Scholar
  46. Martínez-Galván, E., Ramos, J. C., Antón, R., Khodabandeh, R. 2011. Film thickness and heat transfer measurements in a spray cooling system with R134a. J Electron Packag, 133: 011002.Google Scholar
  47. Mignot, G., Dupont, J., Paranjape, S., Ouldrebai, H., Bissels, W. M., Paladino, D., Prasser, H. M. 2018. Measurement of liquid films thickness in a condensing and re-evaporating environment using attenuation of near infrared light. Nucl Eng Des, 336: 64–73.Google Scholar
  48. Morokuma, T., Utaka, Y. 2016. Variation of the liquid film thickness distribution between contacting twin air bubbles during the coalescence process in water and ethanol pools. Int J Heat Mass Tran, 98: 96–107.Google Scholar
  49. Muramatsu, K., Youn, Y., Han, Y., Hasegawa, Y., Shikazono, N. 2015. Numerical study on the effect of initial flow velocity on liquid film thickness of accelerated slug flow in a micro tube. Int J Heat Fluid Fl, 54: 77–86.Google Scholar
  50. Niese, S., Quodbach, J. 2018. Application of a chromatic confocal measurement system as new approach for in-line wet film thickness determination in continuous oral film manufacturing processes. Int J Pharmaceut, 551: 203–211.Google Scholar
  51. Obert, P., Füßer, H.-J., Bartel, D. 2019. Oil distribution and oil film thickness within the piston ring-liner contact measured by laser-induced fluorescence in a reciprocating model test under starved lubrication conditions. Tribol Int, 129: 191–201.Google Scholar
  52. Olgac, U., Muradoglu, M. 2013. Effects of surfactant on liquid film thickness in the Bretherton problem. Int J Multiphase Flow, 48: 58–70.Google Scholar
  53. Patel, R. S., Weibel, J. A., Garimella, S. V. 2017. Characterization of liquid film thickness in slug-regime microchannel flows. Int J Heat Mass Trans, 115: 1137–1143.Google Scholar
  54. Patience, G. S., Chaouki, J. 1993. Gas phase hydrodynamics in the riser of a circulating fluidized bed. Chem Eng Sci, 48: 3195–3205.Google Scholar
  55. Qi, R.-H, Lu, L., Yang, H.-X., Qin, F. 2013. Investigation on wetted area and film thickness for falling film liquid desiccant regeneration system. Appl Energ, 112: 93–101.Google Scholar
  56. Qiu, Q.-G., Zhu, X.-J., Mu, L., Shen, S. 2015. Numerical study of falling film thickness over fully wetted horizontal round tube. Int J Heat Mass Tran, 84: 893–897.Google Scholar
  57. Schmidt, A., Kühnreich, B., Kittel, H., Tropea, C., Roisman, I. V., Dreizler, A., Wagner, S. 2018. Laser based measurement of water film thickness for the application in exhaust after-treatment processes. Int J Heat Fluid Fl, 71: 288–294.Google Scholar
  58. Schubring, D., Ashwood, A. C., Shedd, T. A., Hurlburt, E. T. 2010a. Planar laser-induced fluorescence (PLIF) measurements of liquid film thickness in annular flow. Part I: Methods and data. Int J Multiphase Flow, 36: 815–824.Google Scholar
  59. Schubring, D., Shedd, T. A. 2011. A model for pressure loss, film thickness, and entrained fraction for gas–liquid annular flow. Int J Heat Fluid Fl, 32: 730–739.Google Scholar
  60. Schubring, D., Shedd, T. A., Hurlburt, E. T. 2010b. Planar laser-induced fluorescence (PLIF) measurements of liquid film thickness in annular flow. Part II: Analysis and comparison to models. Int J Multiphase Flow, 36: 825–835.Google Scholar
  61. Shri Vignesh, K., Vasudevan, C., Arunkumar, S., Suwathy, R., Venkatesan, M. 2018. Laser induced fluorescence measurement of liquid film thickness and variation in Taylor flow. Eur J Mech B, 70: 85–92.Google Scholar
  62. Sun, Y.-H., Guo, C.-H., Jiang, Y. Y., Wang, T., Zhang, L. 2018. Transient film thickness and microscale heat transfer during flow boiling in microchannels. Int J Heat Mass Tran, 116: 458–470.Google Scholar
  63. Tan, S., Gao, P., Su, G. 2008. Experimental research on natural circulation complex oscillations under rolling motion conditions. Atomic Energy Science and Technology, 42: 1007–1011.Google Scholar
  64. Tan, S.-C., Su, G.-H., Gao, P.-Z. 2009. Heat transfer model of singlephase natural circulation flow under a rolling motion condition. Nucl Eng Des, 239: 2212–2216.Google Scholar
  65. Tatterson, D. F., Dallman, J. C., Hanratty, T. J. 1977. Drop sizes in annular gas–liquid flows. AIChE J, 23: 68–76.Google Scholar
  66. Tiwari, R., Damsohn, M., Prasser, H.-M. 2014. The effect of initial flow velocity on the liquid film thickness in micro tube accelerated slug flow. Flow Meas Instrum, 40: 124–132.Google Scholar
  67. Wang, B., Chen, B.-W., Tian, R.-F. 2019a. Review of research progress on flow and rupture characteristics of liquid film on corrugated plate wall. Ann Nucl Energy, 132: 741–751.Google Scholar
  68. Wang, B., Chen, B.-W., Tian, R.-F. 2020. Analysis of fluctuation and breakdown characteristics of liquid film on corrugated plate wall. Ann Nucl Energy, 135: 106946.Google Scholar
  69. Wang, B., Tian, R.-F. 2019a. Investigation on flow and breakdown characteristics of water film on vertical corrugated plate wall. Ann Nucl Energy, 127: 120–129.Google Scholar
  70. Wang, B., Tian, R.-F. 2019b. Judgement of critical state of water film rupture on corrugated plate wall based on SIFT feature selection algorithm and SVM classification method. Nucl Eng Des, 347: 132–139.Google Scholar
  71. Wang, B., Tian, R.-F. 2019c. Study on characteristics of water film breakdown on the corrugated plate wall under the horizontal shear of airflow. Nucl Eng Des, 343: 76–84.Google Scholar
  72. Wang, B., Tian, R.-F. 2019d. Study on fluctuation feature and breakdown characteristic of water film on the wall of corrugated plate. Int J Heat Mass Tran, 143: 118501.Google Scholar
  73. Wang, J., Chen, X., Lu, T., Chen, X., Shen, S., Liu, B. 2019b. Three-dimensional film thickness distribution of horizontal tube falling film with column flow. Appl Therm Eng, 154: 140–149.Google Scholar
  74. Wang, R.-L., Lee, B. A., Lee, J. S., Kim, K. Y., Kim, S. 2012. Analytical estimation of liquid film thickness in two-phase annular flow using electrical resistance measurement. Appl Math Model, 36: 2833–2840.MathSciNetzbMATHGoogle Scholar
  75. Werther, J. 1994. Fluid mechanics of large-scale CFB units. In: Circulating Fluidized Bed Technology IV. Avidan, A. A. Ed. New York: AIChE, 1–14.Google Scholar
  76. Xue, T., Yang, L., Ge, P., Qu, L. 2015. Error analysis and liquid film thickness measurement in gas–liquid annular flow. Optik, 126: 2674–2678.Google Scholar
  77. Yang, H.-N., Wei, W., Su, M.-X., Chen, J., Cai, X. 2018. Measurement of liquid water film thickness on opaque surface with diode laser absorption spectroscopy. Flow Meas Instrum, 60: 110–114.Google Scholar
  78. Youn, Y. J., Han, Y., Shikazono, N. 2018. Liquid film thicknesses of oscillating slug flows in a capillary tube. Int J Heat Mass Tran, 124: 543–551.Google Scholar
  79. Youn, Y. J., Muramatsu, K., Han, Y., Shikazono, N. 2015. The effect of initial flow velocity on the liquid film thickness in micro tube accelerated slug flow. Int J Multiphase Flow, 73: 108–117.Google Scholar
  80. Youn, Y. J., Muramatsu, K., Han, Y., Shikazono, N. 2016. The effect of bubble deceleration on the liquid film thickness in microtubes. Int J Heat Fluid Fl, 58: 84–92.Google Scholar
  81. Yu, Y.-X, Ma, L., He, H.-Y., Zheng, Y., Ma, Y. 2017. Research of non-contact measurement for high viscous fluid falling film thickness on spherical series surface. Measurement, 101: 1–8.Google Scholar
  82. Zhang, H., Liu, Q., Qin, B., Bo, H. 2015a. Modeling droplet-laden flows in moisture separators using k-d trees. Ann Nucl Energy, 75: 452–461.Google Scholar
  83. Zhang, H., Liu, Q., Qin, B., Bo, H. 2015b. Simulating particle collision process based on Monte Carlo method. J Nucl Sci Technol, 52: 1393–1401.Google Scholar
  84. Zhang, S., Liu, J.-X., Zuo, Z.-X., Zhang, Y. 2017. An analytical investigation of oil film thickness for the apex seal in a small Wankel rotary engine. Tribol Int, 116: 383–393.Google Scholar
  85. Zhang, W., Johnsson, F., Leckner, B. 1995. Fluid-dynamic boundary layers in CFB boilers. Chem Eng Sci, 50: 201–210.Google Scholar
  86. Zhao, C.-Y, Ji, W.-T., Jin, P.-H., Zhong, Y., Tao, W. 2018. Hydrodynamic behaviors of the falling film flow on a horizontal tube and construction of new film thickness correlation. Int J Heat Mass Tran, 119: 564–576.Google Scholar
  87. Zhou, D.-W., Gambaryan-Roisman, T., Stephan, P. 2009. Measurement of water falling film thickness to flat plate using confocal chromatic sensoring technique. Exp Therm Fluid Sci, 33: 273–283.Google Scholar

Copyright information

© Tsinghua University Press 2019

Authors and Affiliations

  • Bo Wang
    • 1
  • Bingzheng Ke
    • 1
  • Bowen Chen
    • 1
  • Ru Li
    • 1
  • Ruifeng Tian
    • 1
    Email author
  1. 1.Fundamental Science on Nuclear Safety and Simulation Technology LaboratoryHarbin Engineering UniversityHarbinChina

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