SPH Multiphase Simulation of Bubbly Flows: Towards Oil and Water Separation

2013 ◽  
Author(s):  
N. Grenier ◽  
D. Le Touzé ◽  
A. Colagrossi ◽  
G. Colicchio ◽  
M. Antuono
Keyword(s):  
Numerical Solutions ◽  
Bubbly Flow ◽  
Bond Number ◽  
Separation Process ◽  
Bubbly Flows ◽  
Water Separation ◽  
Production Processes ◽  
Physical Effects ◽  
Offshore Industry ◽  
Two Bubbles

The multi-fluid SPH formulation by [1] is studied in the context of engineering flows encountered in the offshore industry where bubbly flows are of importance in some production processes. These particular flows being dominated by viscous and surface tension effects, the considered formulation includes models of these physical effects. This model is then used to simulate viscous incompressible bubbly flows of increasing complexity. These flows include the merging of two bubbles, the separation process in a bubbly flow in a closed tank and then in a simplified separator. Results are compared to numerical solutions when available. The influence of the Bond number on these interfacial flow evolutions is investigated in detail.

Flow Field on Helodeck of a Frigate: A Review

2019 ◽  
Vol 161 (A4) ◽  
Keyword(s):  
Flow Field ◽  
Numerical Solutions ◽  
Offshore Structures ◽  
High Speeds ◽  
High Turbulence ◽  
The Subject ◽  
Offshore Industry ◽  
The Military ◽  
Very High ◽  
Made In

The various functions desired from a frontline warship such as a frigate, corvette or a destroyer, coupled with the requirement of very high speeds and economic viability restricting the size, necessitates a very dense arrangement of weapons and sensors on the top deck and superstructure. Accordingly, Navies across the world have faced several problems with respect to functions for which a good aerodynamic design for these structures is essential. Major issues include smoke nuisance created due to impinging of the ship's exhaust gases on to the top deck leading to possible suction by engine intakes and high turbulence in the ship's air-wake leading to ship aircraft interface concerns. The flow field on the helodeck is extremely complex due to its geometry and interaction with the wake of the ship’s superstructure. A knowledge of this complexity is essential for ensuring safe helo operations on the helodeck. The problem of ship helicopter interaction has hogged the lime light in recent times, due to rising demand for design of warships for increased stealth, especially in the past two decades. Consequently, several researchers in countries with advanced Navies have invested considerable resources towards evolving both experimental and numerical solutions for the problem. However, given the military nature of the operations, open literature on the subject containing details of such research, which can be used as reference material for present work, are limited. Considering the complexities involved in the problem, an attempt has been made in this paper to holistically review the widely scattered and limited literature in this field. A good amount of literature on marine helo applications emerge from the offshore industry. Keeping in mind that the fields of warship design and offshore structures are dissimilar and have their peculiar problems, informed conclusions have been made in drawing lessons from available literature.

Self Organized Structure of Microbubble Plume in a Thin Fluid Layer

2011 ◽  
Author(s):  
Yoshihito Miyagishima ◽  
Tomoaki Watamura ◽  
Yuji Tasaka ◽  
Yuichi Murai
Keyword(s):  
Liquid Phase ◽  
Large Scale ◽  
Fluid Layer ◽  
Bubbly Flow ◽  
The Self ◽  
Bubbly Flows ◽  
Bubble Plume ◽  
Accumulation Pattern ◽  
Thin Fluid ◽  
Self Organized

This study aims to clarify the self-organized structure of microbubble plume as a result of two-way interaction between microbubbles and a flow of the surrounding liquid medium. We observed a sequence on a development of microbubble plumes in a thin fluid layer. Here the microbubbles show accumulation pattern with a different wavenumber depending on the height in the vessel. Variation of spatial wavenumber in the developing process was determined from visualization images, and three areas were distinguished in this process; (1) the area of rising microbubbles with a large wavenumber in a horizontal direction without time dependence; (2) the area of forming a large-scale flow structure, called ‘microbubble plume’ here, which keeps the primary information, horizontal wavenumber of the bubble accumulation with a large wavenumber; (3) the area where the microbubble distribution takes a smaller wavenumber and makes vertical accumulation pattern inside the bubbly flow that is due to the mutual interaction between rising microbubbles and a flow induced by bubbles. To clarify these mutual interactions between liquid and gas phases, we visualized fluid motion of the liquid phase around the microbubble plumes by laser induced fluorescence, LIF. In this way, swaying motions on the tip of rising up bubble plume and liquid phase entrainment into the bubble plumes were visualized. We found the mechanisms for the creation of the self-organized distribution of microbubbles in bubbly flows and its temporal change as the result of the interaction between gas and liquid phase motions in bubbly flows.

Impact of Bubble Size on Flow Response to Transient Pressure Drop Through Converging Nozzle

2020 ◽  
Author(s):  
Aleksey Garbaly ◽  
Thomas Shepard
Keyword(s):  
Transient Response ◽  
Liquid Flow ◽  
Speed Of Sound ◽  
Bubble Size ◽  
Bubbly Flow ◽  
Bubbly Flows ◽  
Chamber Pressure ◽  
Convergent Nozzle ◽  
Flow Rates ◽  
The Impact

Abstract For homogenous two-phase bubbly flows, the theoretical speed of sound is dramatically reduced at moderate void fractions to speeds much lower than the speed of sound for either single phase. This theoretical speed of sound would suggest a propensity for bubbly flows to reach choked conditions when traveling through a convergent nozzle. However, for a bubbly flow to be considered homogenous requires assumptions that may not be realized in practical applications. In this experimental study, a bubbly flow was sent through a convergent nozzle before entering a large chamber. By setting steady flow conditions upstream and then reducing the chamber pressure via a vacuum pump, the transient response in terms of gas and liquid flow rates and upstream channel pressure was determined. The bubble size was carefully varied from ∼0.3–1 mm while holding gas and liquid flow rates constant in order to study how bubble size affects the transient flow characteristics. High-speed imaging was used for measuring the bubbles. Experiments were also conducted at two gas-liquid mass flow ratios. Results are presented to demonstrate the impact of bubble size and gas-liquid ratio on the transient response of upstream gas and liquid flow rates, upstream pressure and exit Mach number to the lowering of pressure downstream of the convergent nozzle. Results are presented both for flows that remained in the bubbly regime and for flows that transitioned to an annular flow regime during a trial.

A comparison of oil-water separation by gravity and electrolysis separation process

2020 ◽  
pp. 1-15 ◽  
Author(s):  
Alaaeddin Elhemmali ◽  
Shams Anwar ◽  
Yahui Zhang ◽  
John Shirokoff
Keyword(s):  
Separation Process ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water

Experimental Investigation on Bubbly Flow in Rectangular Channel Under Rolling Condition

2013 ◽  
Author(s):  
Chaoxing Yan ◽  
Changqi Yan ◽  
Licheng Sun ◽  
Yang Wang ◽  
Daogui Tian ◽  
...  
Keyword(s):  
Bubbly Flow ◽  
Rectangular Channel ◽  
Lateral Distribution ◽  
Lower Wall ◽  
Rolling Angle ◽  
Photographic Recording ◽  
Temperature And Pressure ◽  
Bubble Number ◽  
Two Bubbles ◽  
Vertical Case

Experimental study of rolling effects on characteristics of bubbly flow in a rectangular duct (43 mm×3.25 mm×2000 mm) was performed under ambient temperature and pressure. The characteristics of bubbly flow in vertical, inclined and rolling channels have been obtained through visualization and photographic recording. In the experiment, the gas and liquid superficial velocities ranged from 0.07 m/s to 0.15 m/s and from 1.6 m/s to 2.39 m/s respectively. The bubble clusters contained no less than two bubbles exist in vertical, inclined and rolling channels. With the inclined and rolling angle increase, the bubble clusters tend to contain more bubbles. In vertical case, most bubbles aggregate in the intervals near the narrow wall, thus forms high number fraction peaks at the position around 2x/w = ±0.5. As the inclination and rolling angle increase, the bubble number fraction near the lower wall decreases and that near the upper wall increases. In addition, the number fraction peak close to the lower wall disappears and that near the upper wall becomes higher and sharper at the inclined and rolling angle no less than 10°. There exist no significant differences in bubble lateral distribution under inclined and rolling conditions at the same angle. To identify the influence of rolling on bubble lateral distribution, comparison between lateral buoyancy and additional buoyancy is made theoretically. The results show that the influence of additional buoyancy on lateral bubble distribution can be neglected result from the magnitude of lateral buoyancy is much larger than that of additional buoyancy.

Void Fraction Effect on Added Mass in Bubbly Flow

2014 ◽  
Author(s):  
C. Béguin ◽  
É. Pelletier ◽  
S. Étienne
Keyword(s):  
Liquid Phase ◽  
Void Fraction ◽  
Bubbly Flow ◽  
Added Mass ◽  
Bubbly Flows ◽  
Averaged Equations ◽  
Mass Coefficient ◽  
Spherical Bubbles ◽  
Closure Relations ◽  
Added Mass Coefficient

This paper proposes a relation for the added mass coefficient of spherical bubbles depending on void fraction based on results obtained by a semi-analytical method. This information is essential to completely characterize finely dispersed bubbly flows, where small spherical gas bubbles are present in a continuous liquid phase. Most of the closure relations for Euler-Euler or Euler-Lagrange models are obtained from experiments involving single bubbles. Their applicability to systems with high void fraction is therefore questionable. This paper uses solid harmonics to solve 3D potential flow around bubbles. Several configurations were calculated for different numbers of particles and spatial arrangements. Our results are compared with previous studies. Depending on the model proposed by previous authors, added mass forces could increase or decrease with the void fraction. This paper solves these discrepancies. The main purpose of this work is to develop simple formulas fitting our semi-analytical results. These simple formulas are suitable for further use, particularly as added mass models for multiphase flow averaged equations.

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