Three-dimensional film thickness distribution of horizontal tube falling film with column flow

Wang, Jie; Xue, Cun; Lü, Tao; Chen, Xueshuo; Shen, Shengqiang; Liu, Bo

doi:10.1016/j.applthermaleng.2019.03.041

Cited by 61 publications

(9 citation statements)

References 31 publications

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“…This research is based on the wall contact model, and this research uses copper tubes for research. According to related experimental research Wang et al [10] the doublesided and contact angle of the fluid is set to 10. Fig.…”

Section: Solver Settingsmentioning

confidence: 99%

Influence of Horizontal Tube Bundle Arrangement on Flow and Heat Transfer Properties of Oily Wastewater Spray Falling Film

Shuangshuang,

Zhihao,

Ning

2021

Preprint

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Recently, the spray heat exchanger became an important technology in a sewage source heat pump (SSHP) to recover thermal energy from oily wastewater. Hence, it's necessary to study the heat transfer properties and its enhancements. Among all of the influential factors, the arrangement of the tube bundle is a critical factor that influence the liquid film flow of the falling film, and further has a great impact on heat transfer. Therefore, in this paper, a three-dimensional numerical model of the arrangement of triangular tube bundles is established, using a glycerin-water mixed solution to simulate oily wastewater. The flow pattern of the liquid film under different tube row modes and the influence of heat transfer effects are compared, and the temperature inside the liquid film is analyzed. It was found that there is an obvious difference in the falling film flow outside the horizontal tube between the triangular tube bundle arrangement and the inline tube bundle arrangement. The liquid film flow in the triangular arrangement is more unstable and has a greater impact on the heat transfer of the upper half of the tube. The same phenomenon is observed for the tube bundle below the top row. The local heat transfer coefficient along the circumferential direction of the triangular arrangement is greater than that of the in-line arrangement. Besides, both of the tube bundle arrangements have the phenomenon that the local heat transfer coefficient decreases with the increase in oil content.

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Section: Solver Settingsmentioning

confidence: 99%

Influence of Horizontal Tube Bundle Arrangement on Flow and Heat Transfer Properties of Oily Wastewater Spray Falling Film

Shuangshuang,

Zhihao,

Ning

2021

Preprint

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“…The formation saddle‐shaped lamella was observed in the axial direction. The research of Qiu et al 42 and Wang et al 43 revealed regions in the jet flow pattern, the formation of a crest, liquid FT for various peripheral angles, and axial spreading of the liquid film profile.…”

Section: Introductionmentioning

confidence: 99%

Characterization of column flow regimes on horizontal tubes for falling‐film systems: An experimental approach

Kandukuri

Deshmukh

Katiresan

2022

Asia-Pacific J Chem Eng

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The intertube flow regimes and hydrodynamic behavior of the liquid profile have a significant impact on the functioning of falling-film evaporators. Column flow is one of the fundamental flow modes, which is actively observed in many industrial evaporators. A high-speed digital photographic device is utilized to visualize the complete progression of column flow phases for intertube distances of 10/20/30/40 mm and Reynolds number (Re) values ranging from 41 to 583. The Sobel edge detection algorithm is implemented to quantify the flow parameters for each frame of a sequence. The research results indicated that the column flow regime between the inline horizontal tubes can be broadly classified into the following phases: columnar droplet flow, periodic column flow, satellite drops column flow, drift column flow, and mixing liquid film column flow. The findings show that the liquid jet diameters between the tubes range from 1.6 to 8.46 mm, an increase in the liquid jet diameter with Re and a decrease with tube-to-tube distance. The axial coverage of the liquid film profile beneath the tube differed from 2.07 to 3.99 mm and over the tube surface ranged from 1.14 to 2.68 mm. The formation of dry spots and flooding is a major problem in the operation of falling-film heat exchangers. The shape and size of the liquid jet have a direct impact on the interfacial area; understanding the entire progression of column flow regimes, as well as their characteristics, can help designers avoid the aforementioned problem.

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“…It has several outstanding advantages, including small temperature difference, high heat transfer efficiency, easy separation of vapor, and minimum pressure drop . The horizontal-tube falling film usually exhibits a series of complex fluid behavior, including impact, spreading (along the axial and circumferential directions), convergence, and departure . The falling-film two-phase flow behavior on the horizontal tube dominates the mass and heat transfer directly and thus affects the performance of the system. − …”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Flow Behavior of a Falling Film on Horizontal Tubes: A Comparative Study on Smooth and Finned Tubes

Cao

Xie

et al. 2022

Ind. Eng. Chem. Res.

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In this work, the two-phase flow behavior of a falling film on horizontal smooth and finned tube systems was investigated and compared using a three-dimensional computational fluid dynamics model based on the volume of fluid method. The model was established to capture the microscopic gas–liquid interface of the falling film for smooth and finned tubes. The three-dimensional flow behavior of the falling film, including the liquid film spreading, the film thickness, the velocity distribution, and the effect of Reynolds number (Re) on the film distribution, was investigated systematically. The results show that the liquid film spreads on the smooth tube rapidly and forms a film thickness distribution of “crest-stable-crest”, while the axial spreading of the liquid film is significantly restricted and hindered by the fins on the finned tubes. The falling films of the smooth tube and the finned tube present a staggered column flow and an in-line column flow, respectively. Besides, the axial liquid film spreading on the smooth tube is more sensitive to the Re compared with the finned tubes. The finned tube with a lower fin density achieves better axial spreading, and the finned tube is completely covered by the liquid film at Re = 521 with an optimized liquid column spacing.

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Three-dimensional film thickness distribution of horizontal tube falling film with column flow

Cited by 61 publications

References 31 publications

Influence of Horizontal Tube Bundle Arrangement on Flow and Heat Transfer Properties of Oily Wastewater Spray Falling Film

Influence of Horizontal Tube Bundle Arrangement on Flow and Heat Transfer Properties of Oily Wastewater Spray Falling Film

Characterization of column flow regimes on horizontal tubes for falling‐film systems: An experimental approach

Three-Dimensional Flow Behavior of a Falling Film on Horizontal Tubes: A Comparative Study on Smooth and Finned Tubes

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