Abstract
Gravity-driven horizontal falling-film flow phenomenon is a ground-breaking technology that has been actively used in a wide range of industrial applications, including desalination, petroleum refineries, food processing industries, and refrigeration, among others. A series of experiments and a 2-D two-phase model were developed to investigate falling-film flow regimes, microscopic flow mechanism, and finer flow parameter details. The experiments focused primarily on axial inter-tube flow modes, and circumferential flow parameters were evaluated using numerical simulations. A high-speed digital photographic device was used to capture and visualize the flow pattern. The VOF method is used to capture the liquid–gas interface. The Reynolds number ranged from 41 to 1000, the tube spacing was 10/20/30/40 mm, and the contact angle was 0°. According to the findings, droplet flow has three important phases, detached spherical flow pattern, discrete spherical flow pattern, full neck formation by linked droplets, and droplet flow before reaching column flow. The Reynolds numbers 166, 208, and 250 have departure-site spacing values of approximately 23.84 mm, 18.16 mm, and 14.52 mm, respectively. The flow parameters such as radial film thickness and vortices beneath the tube increase with increasing Reynolds number. As Reynolds number increases, the departure-site spacing and liquid film inter-tube propagation time decrease. The thinnest film zone appeared between 90°and 140°. The velocity magnitude of the liquid film over the test tube is greater than that of the stabilizing tube, despite being close to the distributor. Furthermore, the film velocity on the lower half of the tube wall is slightly higher than that on the upper half of the tube wall.
Similar content being viewed by others
Abbreviations
- d :
-
Diameter of the tube (mm)
- D :
-
Dimensionless film thickness
- \(\overrightarrow{F}\) :
-
Surface tension force (N)
- \(g\) :
-
Gravitational constant (m s−2)
- H :
-
Liquid distributor height (mm)
- \(k\) :
-
Interface curvature
- n :
-
Correlation constant
- n :
-
Normal vector
- S :
-
Tube spacing (mm)
- t :
-
Time, seconds
- \(\rho\) :
-
Density (kg m−3)
- \(\overrightarrow{\vartheta }\) :
-
Mixture velocity (m s−1)
- \({\mu }_{\mathrm{L}}\) :
-
Dynamic viscosity of the water (kg m−1 s−1)
- \(\Gamma\) :
-
Flow rate of a liquid on one side of the circular tube (kg m−1 s−1)
- \(\delta\) :
-
Liquid film thickness (mm)
- \(\sigma\) :
-
Surface tension (N m−1)
- θ:
-
Circumferential angle (°)
- Re:
-
Reynolds number
- CFD:
-
Computational fluid dynamics
- CSF:
-
Continuum surface force
- DFT:
-
Dimensionless film thickness
- PISO:
-
Pressure implicit with splitting of operator
- PRESTO:
-
Pressure staggering option
- VOF:
-
Volume of fluid
- \({\alpha }_{\mathrm{q}}\) :
-
Volume fraction of phase q
- Eq.:
-
Equation
- \(L\) :
-
Liquid
- \(G\) :
-
Gas
- s :
-
Solid
- q :
-
Phase
References
Zhang L, Akiyama T. How to recuperate industrial waste heat beyond time and space. Int J Exergy. 2009;6(2):214–27. https://doi.org/10.1504/IJEX.2009.023999.
Karmakar A, Acharya S. Wettability effects on falling film flow and heat transfer over horizontal tubes in jet flow mode. J Heat Trans. 2020. https://doi.org/10.1115/1.4048088.
Fernández-Seara J, Pardiñas ÁÁ. Refrigerant falling film evaporation review: description, fluid dynamics and heat transfer. Appl Therm Eng. 2014;64(1–2):155–71. https://doi.org/10.1016/j.applthermaleng.2013.11.023.
Aly S, Jawad J, Manzoor H, Simson S, Lawler J, Mabrouk AN. Pilot testing of a novel integrated multi effect distillation-absorber compressor (MED-AB) technology for high performance seawater desalination. Desalination. 2022;1(521): 115388. https://doi.org/10.1016/j.desal.2021.115388.
Hesari F, Salimnezhad F, Manesh MH, Morad MR. A novel configuration for low-grade heat-driven desalination based on cascade MED. Energy. 2021;15(229): 120657. https://doi.org/10.1016/j.energy.2021.120657.
Sun C, Liu L, Li Y, Cao X, Han H. Experimental and numerical study on the falling film flow characteristics outside circular tube applied in floating liquefied natural gas (FLNG) under offshore conditions. Int J Heat Fluid Flow. 2021;1(92): 108883. https://doi.org/10.1016/j.ijheatfluidflow.2021.108883.
Cyklis P. Industrial scale engineering estimation of the heat transfer in falling film juice evaporators. Appl Therm Eng. 2017;1(123):1365–73. https://doi.org/10.1016/j.applthermaleng.2017.05.194.
Narváez-Romo B, Chhay M, Zavaleta-Aguilar EW, Simões-Moreira JR. A critical review of heat and mass transfer correlations for LiBr-H2O and NH3-H2O absorption refrigeration machines using falling liquid film technology. Appl Therm Eng. 2017;1(123):1079–95. https://doi.org/10.1016/j.applthermaleng.2017.05.092.
Xu L, Ge M, Wang S, Wang Y. Heat-transfer film coefficients of falling film horizontal tube evaporators. Desalination. 2004;15(166):223–30. https://doi.org/10.1016/j.desal.2004.06.077.
Jiang JF, Li SF, Liu ZH. Study on heat transfer and cold storage characteristics of a falling film type of cold energy regenerator with PCM. Appl Therm Eng. 2018;1(143):676–87. https://doi.org/10.1016/j.applthermaleng.2018.07.127.
Roques JF, Thome JR. Falling films on arrays of horizontal tubes with R-134a, part II: flow visualization, onset of dryout, and heat transfer predictions. Heat Transfer Eng. 2007;28(5):415–34. https://doi.org/10.1080/01457630601163736.
Yan WM, Pan CW, Yang TF, Ghalambaz M. Experimental study on fluid flow and heat transfer characteristics of falling film over tube bundle. Int J Heat Mass Transf. 2019;1(130):9–24. https://doi.org/10.1016/j.ijheatmasstransfer.2018.10.070.
Zhang H, Yin D, You S, Zheng W, Li B, Zhang X. Numerical and experimental investigation on the heat and mass transfer of falling film and droplet regimes in horizontal tubes LiBr-H2O absorber. Appl Therm Eng. 2019;5(146):752–67. https://doi.org/10.1016/j.applthermaleng.2018.10.046.
Hu X, Jacobi AM. The intertube falling film Part 1—Flow characteristics, mode transitions, and hysteresis. J Heat Trans. 1996;10(1115/1):2822676.
Armbruster R, Mitrovic J. Patterns of falling film flow over horizontal smooth tubes. InInternational Heat Transfer Conference Digital Library 1994. Begel House Inc.. DOI: https://doi.org/10.1615/IHTC10.460.
Chen J, Zhang R, Niu R. Numerical simulation of horizontal tube bundle falling film flow pattern transformation. Renew Energy. 2015;1(73):62–8. https://doi.org/10.1016/j.renene.2014.08.007.
Mohamed AM. Flow behavior of liquid falling film on a horizontal rotating tube. Exp Therm Fluid Sci. 2007;31(4):325–32. https://doi.org/10.1016/j.expthermflusci.2006.05.004.
Wang X, Hrnjak PS, Elbel S, Jacobi AM, He M. Flow modes and mode transitions for falling films on flat tubes. J Heat Trans. 2012. https://doi.org/10.1115/1.4005095.
Qu Z, Ma Z, Chen J, Zhang J. Falling film flow mode transitions on an array of horizontal tubes under nonuniform liquid distribution conditions. Exp Thermal Fluid Sci. 2019;1(109): 109901. https://doi.org/10.1016/j.expthermflusci.2019.109901.
Wang X, He M, Lv K, Fan H, Jacobi AM. Effects of liquid supply method on falling-film mode transitions on horizontal tubes. Heat Trans Eng. 2013;34(7):562–79. https://doi.org/10.1080/01457632.2013.730398.
W. Nusselt, 1916. Die oberflächenkondensation des wasserdampfes zeitschrift.
Hou H, Bi Q, Ma H, Wu G. Distribution characteristics of falling film thickness around a horizontal tube. Desalination. 2012;31(285):393–8. https://doi.org/10.1016/j.desal.2011.10.020.
Zhang JT, Wang BX, Peng XF. Falling liquid film thickness measurement by an optical-electronic method. Rev Sci Instrum. 2000;71(4):1883–6. https://doi.org/10.1063/1.1150557.
Zaitsev DV, Kabov OA, Evseev AR. Measurement of locally heated liquid film thickness by a double-fiber optical probe. Exp Fluids. 2003;34(6):748–54. https://doi.org/10.1007/s00348-003-0621-1.
Chen X, Shen S, Wang Y, Chen J, Zhang J. Measurement on falling film thickness distribution around horizontal tube with laser-induced fluorescence technology. Int J Heat Mass Trans. 2015;1(89):707–13. https://doi.org/10.1016/j.ijheatmasstransfer.2015.05.016.
Han Y, Kanno H, Ahn YJ, Shikazono N. Measurement of liquid film thickness in micro tube annular flow. Int J Multiph Flow. 2015;1(73):264–74. https://doi.org/10.1016/j.ijmultiphaseflow.2015.03.016.
Jayakumar A, Balachandran A, Mani A, Balasubramaniam K. Falling film thickness measurement using air-coupled ultrasonic transducer. Exp Therm Fluid Sci. 2019;1(109): 109906. https://doi.org/10.1016/j.expthermflusci.2019.109906.
Qiu QG, Jiang WG, Shen SQ, Zhu XJ, Mu XS. Numerical investigation on characteristics of falling film in horizontal-tube falling film evaporator. Desalin Water Treat. 2015;55(12):3247–52. https://doi.org/10.1080/19443994.2014.968907.
Tahir F, Mabrouk A, Koç M. Impact of surface tension and viscosity on falling film thickness in multi-effect desalination (MED) horizontal tube evaporator. Int J Therm Sci. 2020;1(150): 106235. https://doi.org/10.1016/j.ijthermalsci.2019.106235.
Ji G, Wu J, Chen Y, Ji G. Asymmetric distribution of falling film solution flowing on hydrophilic horizontal round tube. Int J Refrig. 2017;1(78):83–92. https://doi.org/10.1016/j.ijrefrig.2017.03.022.
Qiu Q, Zhu X, Mu L, Shen S. Numerical study of falling film thickness over fully wetted horizontal round tube. Int J Heat Mass Transf. 2015;1(84):893–7. https://doi.org/10.1016/j.ijheatmasstransfer.2015.01.024.
Wang Q, Li M, Xu W, Yao L, Liu X, Su D, Wang P. Review on liquid film flow and heat transfer characteristics outside horizontal tube falling film evaporator: Cfd numerical simulation. Int J Heat Mass Transf. 2020;1(163): 120440. https://doi.org/10.1016/j.ijheatmasstransfer.2020.120440.
Yung D, Lorenz JJ, Ganic EN. Vapor/liquid interaction and entrainment in falling film evaporators. J Heat Trans. 1980. https://doi.org/10.1115/1.3244242.
Killion JD, Garimella S. Gravity-driven flow of liquid films and droplets in horizontal tube banks. Int J Refrig. 2003;26(5):516–26. https://doi.org/10.1016/S0140-7007(03)00009-4.
Liu S, Shen S, Mu X, Guo Y, Yuan D. Experimental study on droplet flow of falling film between horizontal tubes. Int J Multiph Flow. 2019;1(118):10–22. https://doi.org/10.1016/j.ijmultiphaseflow.2019.05.008.
Kandukuri P, Deshmukh S, Katiresan S. Characterization of column flow regimes on horizontal tubes for falling-film systems: an experimental approach. Asia-Pac J Chem Eng. 2022;17(2): e2745. https://doi.org/10.1002/apj.2745.
Peng-o T, Chaikan P. High performance and energy efficient sobel edge detection. Microprocess Microsyst. 2021;1(87): 104368. https://doi.org/10.1016/j.micpro.2021.104368.
Abasi SA, Tehran M, Fairchild MD. Colour metrics for image edge detection. Color Res Appl. 2020;45(4):632–43. https://doi.org/10.1002/col.22494.
Abdullah SS, Rajasekaran MP. Modified Sobel mask to locate knee joint boundaries. 3C Tecnología. Glosas De innovaci on Aplicadas a La Pyme. 2020:195–205. DOI: https://doi.org/10.17993/3ctecno.2020.specialissue4.195-205
Jing M, Du Y. Flank angle measurement based on improved Sobel operator. Manufact Lett. 2020;1(25):44–9. https://doi.org/10.1016/j.mfglet.2020.07.002.
Hirt CW, Nichols BD. Volume of fluid (VOF) method for the dynamics of free boundaries. J Comput Phys. 1981;39(1):201–25. https://doi.org/10.1016/0021-9991(81)90145-5.
Brackbill JU, Kothe DB, Zemach C. A continuum method for modeling surface tension. J Comput Phys. 1992;100(2):335–54. https://doi.org/10.1016/0021-9991(92)90240-Y.
Killion JD, Garimella S. Pendant droplet motion for absorption on horizontal tube banks. Int J Heat Mass Trans. 2004;47(19–20):4403–14. https://doi.org/10.1016/j.ijheatmasstransfer.2004.04.032.
Zheng Y, Yang S, Zhao X, Wang Z, Yuan J, Ma X. The transient flow mechanism and intermittent film thickness evolution regulation of droplet mode for horizontal tube falling film. Eur J Mech-B/Fluids. 2021;1(89):151–60. https://doi.org/10.1016/j.euromechflu.2021.02.008.
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Springer Nature or its licensor holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Kandukuri, P., Deshmukh, S. & Katiresan, S. Experimental and numerical study of falling-film hydrodynamics and droplet flow regimes over horizontal tubes. J Therm Anal Calorim 148, 2781–2798 (2023). https://doi.org/10.1007/s10973-022-11624-w
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10973-022-11624-w