Research of vertical falling film behavior in scrubbing-cooling tube

Yan, Liucheng; Wang, Yifei; Wu, Ziwei; Dai, Zhenghua; Yu, Guangsuo; Wang, Fuchen

doi:10.1016/j.cherd.2016.11.010

Cited by 17 publications

(5 citation statements)

References 20 publications

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“…The film thickness in a given cross section is measured horizontally from the wall to the point where L = 0.5 . This approach is shown by Vieiro et al (2013) to provide a good approximation of the film thickness and adopted by Chen et al (2015), Yan et al (2017).…”

Section: Time Step Independencementioning

confidence: 99%

CFD modeling of liquid film reversal of two-phase flow in vertical pipes

Hussein

Al–Sarkhi

Badr

et al. 2019

J Petrol Explor Prod Technol

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The phenomenon of two-phase flows is characterized by its wide range of presence in nature and industrial applications. In gas and oil production, the simultaneous two-phase flow of gases and liquids often occurs in gas wells. The produced gases flow rate decreases over the years until reaching a critical flow rate when they lose their ability to lift the associated liquids upward and the liquid film reverses direction, which triggers liquid loading. Liquid loading causes the produced liquids to accumulate in the bottom of the wellbore, which causes a high back pressure that reduces the well production rate till production is ceased eventually. The critical gas velocity exists in the churn flow regime which is mainly characterized by the oscillatory behavior of the liquids flow field. This study employs CFD techniques to model the churn flow in a 3-inchdiameter vertical pipe near the critical gas flow rate for different liquid flow rates. This work utilizes the two-fluid Eulerian model along with the RNG (Re-Normalization Group) k-ε turbulence model to investigate the behavior of the flow field in a two-dimensional axisymmetric computational domain. Simulations were carried out using the commercial software ANSYS Fluent 18.2 with air and water as the two working fluids. The model results showed a good agreement with the experimental data and proved the mesh and time independence of the model. Oscillatory behaviors of the liquid film flow rate, shear stress, and pressure were observed along with the formation of interfacial waves. Detailed information about the velocity, shear stress, and pressure behaviors is presented. Accordingly, recommendations are suggested for future considerations.

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Section: Time Step Independencementioning

confidence: 99%

CFD modeling of liquid film reversal of two-phase flow in vertical pipes

Hussein

Al–Sarkhi

Badr

et al. 2019

J Petrol Explor Prod Technol

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“…The circumferential non-uniformity and instability of the liquid film at the inlet also increases when Re l increases. The liquid film at the position of 0° flows to the thinner position (such as 8 and 16°) on both sides due to insufficient cohesion . At the same time, it will increase the probability of liquid film surface rupture and droplet entrainment when Re l reaches a certain critical value.…”

Section: Resultsmentioning

confidence: 99%

“…In previous studies, the distribution of liquid film on the circumferential direction is uneven. 35 Therefore, it is not accurate to choose the thickness of liquid film on different circumferential direction to observe the flow characteristics of liquid film. Therefore, this paper chooses the thickness of liquid film at different axial positions of 0° position for comparison.…”

Section: Resultsmentioning

confidence: 99%

“…The liquid film at the position of 0° flows to the thinner position (such as 8 and 16°) on both sides due to insufficient cohesion. 35 At the same time, it will increase the probability of liquid film surface rupture and droplet entrainment when Re l reaches a certain critical value. In addition, the fluctuation amplitude of the liquid film also increases with the increase of Re l , which will eventually lead to the rupture of the liquid film surface and change the waveform of the liquid film.…”

Section: Resultsmentioning

confidence: 99%

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Effect of Structural Optimization of Scrubbing Cooling Rings on Vertical Falling Film Flow Characteristics

Huang

Wang

et al. 2022

ACS Omega

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In order to study the influence of the structural optimization of the scrubbing cooling ring in the scrubbing cooling chamber on the flow characteristics of the vertical falling film, the flow characteristics of the turbulent falling film in the rising section of the development region at different internal platform heights of the scrubbing cooling ring and a high Reynolds number were studied by FLUENT software. First, the correctness of the model was verified by the maximum error of simulation and experimental results of no more than 9.836%. Then, the distribution of liquid film thickness (δ), velocity ( V ), and turbulence intensity ( I z ) at 0° of the tube in the axial direction x = 0–500 mm were calculated and obtained when the platform height ( H ) was 0–30 mm and the liquid film Reynolds number ( Re l ) = 1.1541 × 10 4 –3.4623 × 10 4 . The results showed that δ in the entrance region increased sharply due to the “jet” effect with solid wall constraints formed by the structure of the water inlet pipe and the scrubbing cooling ring. On the contrary, the liquid film in the fully developed region showed a stable fluctuation trend due to the weakening of the “jet” effect. When H = 30 mm, the change of δ was relatively stable and the change of I z was small, indicating that this platform height is conducive to the stable and uniform distribution of the liquid film. In addition, when Re l < 1.1541 × 10 4 , the liquid film was unstable due to the low flow rate and insufficient cohesion of the liquid film, but V increased slightly. In addition, with the increase of Re l , δ did not change significantly along the axial direction, that is, the Plateau–Rayleigh hindered the growth of δ. Finally, the empirical formula for δ applicable to Re l = 1.1541 × 10 4 –3.4623 × 10 4 at the axial fixed position was fitted for the first time.

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“…High-temperature crude coal gas containing molten slags is spray cooled by the scrubbing–cooling ring at first and then flows downstream along the scrubbing–cooling tube attached to the quenching water film and finally enters the liquid bath, in which the washing and cooling of crude coal gas are performed. Most of the studies in the scrubbing–cooling chamber are carried out on a gas–liquid two-phase flow, such as gas–liquid separation, , falling film flow, , and reverse buoyant flow. − Sphere particles are usually employed as the solid phase in the studies of the gas–solid–liquid three-phase flow in a scrubbing–cooling chamber, , however, the slag particles are mostly nonspherical in an actual gasifier. The most representative nonspherical particles are fiber particles with a certain aspect ratio, which are anisotropic, have orientation distributions and interact with each other.…”

Section: Introductionmentioning

confidence: 99%

Local Distributions of Bubble Velocity and Interfacial Area in the Slender Particle-Containing Scrubbing–Cooling Chamber of an Entrained-Flow Gasifier

Zhao

Peng

Wang

et al. 2020

Ind. Eng. Chem. Res.

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Radial bubble velocities, chord lengths, and local gas holdups were measured by a dual-tip conductivity probe in a slender particle-containing scrubbing–cooling chamber. The annulus region of the bubbling bed was divided into three regions according to the radial distributions of bubble velocity, bubble size, and local gas holdup. Bubble velocity distributions were obtained by the kernel density estimation, and the relationships between mean bubble velocity and diameter were discussed. The interfacial area was calculated by the size distribution of total bubbles in the bed which was transformed from that of total bubbles touching the probe by an analytical transformation method. Effects of superficial gas velocity, fiber volume fraction, and aspect ratio on the distributions of bubble velocity and interfacial area were discussed. The experimental interfacial area values were in good agreement with the calculated ones obtained by the modified Besagni and Inzoli correlation.

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Research of vertical falling film behavior in scrubbing-cooling tube

Cited by 17 publications

References 20 publications

CFD modeling of liquid film reversal of two-phase flow in vertical pipes

CFD modeling of liquid film reversal of two-phase flow in vertical pipes

Effect of Structural Optimization of Scrubbing Cooling Rings on Vertical Falling Film Flow Characteristics

Local Distributions of Bubble Velocity and Interfacial Area in the Slender Particle-Containing Scrubbing–Cooling Chamber of an Entrained-Flow Gasifier

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