Numerical simulation of non-linear film variation and heat transfer characteristics in falling film evaporation around in-line horizontal tubes

Yıl 2024, Cilt: 10 Sayı: 3, 541 - 551, 21.05.2024

Awdhesh Kumar Poddar Nirmal Kant Singh

Öz

In falling film evaporation on a horizontal tube, heat transfer phenomena are highly unpredictable due to uncertainties in the determination of film thickness around the tube, local dry-out condition, geometrical configuration, tube spacing etc. Numerical simulations of falling film evaporation around a single horizontal tube are performed using volume of fluid (VOF) method. Film thickness around the circumference of the horizontal tube is investigated and validated with Nusselt correlations and experiments carried out by researchers. The results are in good agreement with experimental investigations performed by various researchers. Influence of inter-tube spacing, film Reynolds number and variation of diameter on the formation of film thickness are studied and it is found that the film thickness is minimum around 100o-120o circumferential position, whereas Nusselt correlation predicted the minimum value at 90o circumferential position. Wall shear stress and heat transfer are also studied around the horizontal cylinder. It is seen that near the impingement zone, fluctuation of wall shear stress and heat transfer are very high, showing abnormal behaviour in this zone.

Anahtar Kelimeler

Falling Film, Film Thickness, Heat Transfer, Horizontal Tube

Kaynakça

• [1] Wen T, Lu L, He W, Min Y. Fundamentals and applications of CFD technology on analyzing falling film heat and mass exchangers: A comprehensive review. Appl Energy 2020;261:114473. [CrossRef]
• [2] Bouman S, Waalewijn R, Jong Pd, Linden HVD. Design of falling‐film evaporators in the dairy industry. Int J Dairy Technol 1993;46:100–106. [CrossRef]
• [3] Cyklis P. Industrial scale engineering estimation of the heat transfer in falling film juice evaporators. Appl Therm Eng 2017;123:1365–1373. [CrossRef]
• [4] Armbruster R, Mitrovic J. Evaporative cooling of a falling water film on horizontal tubes. Exp Therm Fluid Sci 1998;18:183–194. [CrossRef]
• [5] Mohammed H, Abed AM, Wahid M. The effects of geometrical parameters of a corrugated channel with in out-of-phase arrangement. Int Comm Heat Mass Transf 2013;40:47–57. [CrossRef]
• [6] Karademir H, Özçelik G, Açikgöz Ö, Dalkiliç AS, İnce İT, Meyer J, et al. Comprehensive review on the flow characteristics of two-phase flows in inclined tubes. J Therm Engineer 2021;7:483–549. [CrossRef]
• [7] Bergman TL, Incropera FP, DeWitt DP, Lavine AS. Fundamentals of heat and mass transfer. New York: John Wiley & Sons; 2011.
• [8] Mitrovic J. Preventing formation of dry patches in seawater falling film evaporators. Desalin Water Treat 2011;29:149–157. [CrossRef]
• [9] Gstoehl D, Roques J, Crisinel P, Thome J. Measurement of falling film thickness around a horizontal tube using a laser measurement technique. Heat Transf Engineer 2004;25:28–34. [CrossRef]
• [10] Nusselt W. Die Oberflächenkondensation des Wasserdampfes. Z VDI 1916;60:541–546.
• [11] Chen J, Zhang R, Niu R. Numerical simulation of horizontal tube bundle falling film flow pattern transformation. Renew Energy 2015;73:62–68. [CrossRef]
• [12] Dukler A. Characteristics of flow in falling liquid film. Proc Chem Eng Prog Symp Series 1952;48:557–563.
• [13] Abraham R, Mani A. Heat transfer characteristics in horizontal tube bundles for falling film evaporation in multi-effect desalination system. Desalination 2015;375:129–137. [CrossRef]
• [14] Wang X, He M, Fan H, Zhang Y. Measurement of falling film thickness around a horizontal tube using laser-induced fluorescence technique. J Phys: Conf Ser 2009;147:012039. [CrossRef]
• [15] Liu S, Mu X, Shen S, Li C, Wang B. Experimental study on the distribution of local heat transfer coefficient of falling film heat transfer outside horizontal tube. Int J Heat Mass Transf 2021;170:121031. [CrossRef]
• [16] Zhang J, Wang B, Peng X. Falling liquid film thickness measurement by an optical-electronic method. Rev Sci Instrum 2000;71:1883–1886. [CrossRef]
• [17] Zhao CY, Ji WT, Jin PH, Zhong YJ, Tao WQ. Experimental study of the local and average falling film evaporation coefficients in a horizontal enhanced tube bundle using R134a. Appl Therm Engineer 2018;129:502–511. [CrossRef]
• [18] Liu Z, Yi J. Falling film evaporation heat transfer of water/salt mixtures from roll-worked enhanced tubes and tube bundle. Appl Therm Engineer 2002;22:83–95. [CrossRef]
• [19] Pu L, Li Q, Shao X, Ding L, Li Y. Effects of tube shape on flow and heat transfer characteristics in falling film evaporation. Appl Therm Engineer 2019;148:412–419. [CrossRef]
• [20] Bayareh M. Numerical simulation and analysis of heat transfer for different geometries of corrugated tubes in a double pipe heat exchanger. J Therm Engineer 2019;5:293–301. [CrossRef]
• [21] Panda S, Kumar R. A review on effect of various artificial roughness on heat transfer enhancement in a channel flow. J Therm Engineer 2021;7:1267–12301. [CrossRef]
• [22] Sundravel A, Suresh S, Deenadayalan S. Numerical investigation of supercritical heat transfer of water flowing in vertical and horizontal tube with emphasis of gravity effect. J Therm Engineer 2021;7:1541–1555. [CrossRef]
• [23] 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;130:9–24. [CrossRef]
• [24] Hirt CW, Nichols BD. Volume of fluid (VOF) method for the dynamics of free boundaries. J Comput Phys 1981;39:201–225. [CrossRef]
• [25] Hou H, Bi Q, Ma H, Wu G. Distribution characteristics of falling film thickness around a horizontal tube. Desalination 2012;285:393–398. [CrossRef]
• [26] Singh N, Kumar Poddar A. Numerical study of liquid film formation around tubes of horizontal falling film evaporator. J Appl Fluid Mech 2021;14:1045–1052. [CrossRef]