A novel lift-off diameter model for boiling bubbles in natural gas liquids transmission pipelines

Jia, Wenlong; Lin, Youzhi; Yang, Fan; Li, Changjun

doi:10.1016/j.egyr.2020.02.014

Cited by 10 publications

(6 citation statements)

References 25 publications

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“…Saffman (1965) [ 16 ], derived an expression for the lift force acting on spherical bubbles at laminar regime under the presence of a velocity gradient, and a modified equation was presented by Mei and Klausner (1994) [ 17 ] where is the lift coefficient, is the relative velocity between the fluid and the droplet and a is the bubble or droplet’s radius. In regard to the relative velocity , no model for the bubble sliding velocity exists in the literature, [ 12 ], but in view of the several uncertainties in the analysis we assume a bubble sliding velocity half of the local fluid, i.e., as suggested by [ 12 ] and [ 13 ], which seems that is the best figure which agrees well with the predictions by those authors in the calculation of the lift. For small Reynolds numbers, the lift coefficient is simplified as [ 12 ]: where is the radial velocity gradient which can already be calculated from Eq.…”

Section: Methodssupporting

confidence: 61%

“…The simplifying assumptions valid for a first analytical assessment of the problem are as follows: The channels between fibres are represented by its hydraulic diameter, i.e, by an equivalent circular channel Laminar flow. The typical values for Reynolds number for medical mask are below 50, and thus the assumption is more than justified Airborne particles are spherical For preliminary calculations, it is taken the relative velocity between the particle and the flow half of the local fluid velocity as suggested by [ 12 , 13 ] To begin with, let us consider a traditional face mask. It is basically formed by a stack of -vertical layers -generally 3 of them for the case of N95s.…”

Section: Methodsmentioning

confidence: 99%

“…For preliminary calculations, it is taken the relative velocity between the particle and the flow half of the local fluid velocity as suggested by [ 12 , 13 ]…”

Section: Methodsmentioning

confidence: 99%

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The aerolayer: airborne filtration by aerodynamic focusing and growth

2023

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In this work, a novel approach for airborne filtration with particular reference to medical (non-oil) medical mask is discussed. Here, and contrariwise to current approaches, filtration is attained neither by reducing the hydraulic diameter of the pore nor by increasing the fibre layers thickness-both of them with a strong penalty in the breathability of the mask, but rather by aerodynamic focussing and growth of the particles themselves. Aerodynamic focussing of particles is achieved by a proper simple parallel rearrangement of the traditional crisscrossing fibres-a configuration which we called the aerolayer; and the growth by coalescence. Utilizing a simplified geometrical and physical model, an expression for the required length of the aerolayer was derived. It is shown that the aerolayer is not only able to increase the probability of capture for small particles but also can potentially improve the breathability by reduction of the total thickness of the current layers required. Additional R &D is required in order to arrive to the most optimized practical design of the aerolayer.

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Section: Methodssupporting

confidence: 61%

Section: Methodsmentioning

confidence: 99%

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The aerolayer: airborne filtration by aerodynamic focusing and growth

2023

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“…To analyze the commissioning process in undulating terrain, we firstly classify the pipeline in terms of the inclination angle, backpressure, and elevation differences, which also allows exploring the terrain in terms of the inclination angle and elevation difference [38]. In an actual pipeline, the inclination angle usually refers to the angle between the centerline of the pipeline and the horizontal direction (ranging from −90 • to 90 • ), which is positive in the counterclockwise direction and is often replaced by a slope in practical engineering [39]. The slope is calculated by dividing the height difference of a certain section by the mileage difference, which is the tangent of the pipe angle.…”

Section: Division Of Different Pipeline Terrainsmentioning

confidence: 99%

Modeling of Gas Migration in Large Elevation Difference Oil Transmission Pipelines during the Commissioning Process

Feng¹,

Zhu²,

Song³

et al. 2022

Energies

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Oil pipeline construction and operation in mountainous areas have increased in southwestern China, with oil consumption increasing. Such liquid pipelines laid in mountainous areas continuously undulate along the terrain, resulting in many large elevation difference pipe segments. Serious gas block problems often occur during the commissioning process of these pipelines due to the gas/air accumulation at the high point of the pipe, which causes pipeline overpressure and vibration, and even safety accidents such as bursting pipes. To solve this problem, the gas–liquid replacement model and its numerical solution are established with consideration of the initial gas accumulation formation and the gas segment compression processes in a U-shaped pipe during the initial start-up operation. Additionally, considering the interactions of the gas-phase transfer in the continuous U-shaped pipe, and the influence of the length, inclination angle, and backpressure on the air vent process, the gas migration model for a continuous U-shaped pipe is established to predict the gas movement process. Finally, the field oil pipe production data were applied to verify the model. The results demonstrate that the maximum deviation between the calculated pressure during the start-up process and real data is 0.3 MPa, and the critical point of crushing the gas in the pipe section is about 0.2 Mpa. Additionally, the results show that the mass transfer of the gas section in the multi-pipe hydraulic air vent process causes the gas accumulation section to increase in downstream of the pipe. This study’s achievements can provide theoretical guidance and technical support for the safe and stable operation of continuous undulating liquid pipelines with large drops.

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“…The continuous progress of computer technology leads to the rapid development of computational fluid dynamics (CFD) technology [4,13]. Relying on theoretical modeling basis, CFD methods can not only help to understand fluid dynamics problems intuitively and clearly, providing references for experiments and research design, but also greatly save labor, material and time [6,14,15]. Therefore, CFD methods are gradually becoming an important tool for studying flow problems together with experimental fluid dynamics.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Elbow Erosion in Shale Gas Fields under Gas-Solid Two-Phase Flow

Hong

et al. 2021

Energies

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Erosion is one of the most common forms of material failure and equipment damage in gas transmission pipelines. Shale gas fields use hydraulic fracturing whereby solid particles are often carried in the gas flow, and the pipeline is in a high-pressure state, which is more likely to cause erosion. The prediction of particle erosion regulation in gas-solid two-phase flow is an effective means to ensure the safe operation of shale gas fields. In this paper, an integrated CFD-DPM model is established to investigate the erosion of 90° elbow in a shale gas field under gas-solid two-phase flow, employing the realizable k-ε turbulence model, discrete phase model, and erosion rate prediction model. The reliability of the proposed numerical models is verified by comparing the predicted data with the experimental data. Moreover, the effects of six important factors on maximum erosion rate are analyzed, including gas velocity, mass flow rate of sand particles, particle diameter, shape coefficient of sand particles, pipeline diameter, elbow radius of curvature. Specifically, the results indicate that the gas velocity, mass flow rate and shape coefficient of sand particles are positively correlated with the maximum erosion rate, while the pipe diameter and the elbow radius of curvature are negatively correlated with the maximum erosion rate. A new correlation was developed, which included four dimensionless groups, namely Reynolds number, diameter ratio, density ratio and particle number. The correlation can be used to predict maximum corrosion rate of elbows. This work can provide data reference and theoretical basis for mitigating the erosion rate of pipelines and managing the integrity of gas pipelines.

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A novel lift-off diameter model for boiling bubbles in natural gas liquids transmission pipelines

Cited by 10 publications

References 25 publications

The aerolayer: airborne filtration by aerodynamic focusing and growth

The aerolayer: airborne filtration by aerodynamic focusing and growth

Modeling of Gas Migration in Large Elevation Difference Oil Transmission Pipelines during the Commissioning Process

Numerical Simulation of Elbow Erosion in Shale Gas Fields under Gas-Solid Two-Phase Flow

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