Lattice Boltzmann Simulation of Jet Breakup and Droplet Formation in Immiscible Liquid-Liquid System

2017 ◽  
Author(s):  
Shimpei Saito ◽  
Yutaka Abe ◽  
Akiko Kaneko ◽  
Yuzuru Iwasawa ◽  
Kazuya Koyama
Keyword(s):  
Lattice Boltzmann ◽  
Numerical Stability ◽  
Three Dimensional ◽  
Droplet Formation ◽  
Liquid System ◽  
Immiscible Liquid ◽  
Two Phase ◽  
Jet Breakup ◽  
Lattice Boltzmann Simulation ◽  
Lattice Boltzmann Simulations

It is essential to understand the fundamental processes between melt jet and coolant during a postulated core-disruptive accident of a sodium-cooled fast reactor. In the present study, jet breakup and droplet formation in immiscible liquid-liquid system were studied numerically. A lattice Boltzmann two-phase model was modified in framework of three-dimensional 27-lattice to enhance the numerical stability. This model was applied to the conditions of jet breakup simulations. The present lattice Boltzmann simulations qualitatively reproduced the characteristic transitions of breakup regimes.

Jet Breakup and Droplet Formation in Immiscible Liquid-Liquid System

2016 ◽  
Author(s):  
Shimpei Saito ◽  
Yuzuru Iwasawa ◽  
Yutaka Abe ◽  
Akiko Kaneko ◽  
Tetsuya Kanagawa ◽  
...  
Keyword(s):  
Weber Number ◽  
Droplet Diameter ◽  
Droplet Formation ◽  
Liquid System ◽  
Immiscible Liquid ◽  
Satellite Droplet ◽  
Breakup Length ◽  
Jet Breakup ◽  
Fundamental Process ◽  
Median Diameter

Mitigative measures against the event of a core disruptive accident (CDA) are of the importance from the viewpoint of safety of a sodium-cooled fast reactor (SFR). If the CDA occurs, the so-called post-accident heat removal must be surely achieved. The present study focuses on the scenario that the molten materials are injected into the lower plenum as jets. The jet breakup behavior during the CDA will be very complicated. Therefore, a specialized study on the fundamental process during the jet breakup is believed to be an effective approach. The aim of this paper is to understand the fundamental process of hydrodynamic interaction of jet breakup and droplet formation Using the immiscible liquid-liquid system, water and silicon oil as the test fluids, visualization via high-speed videography was performed. From the visualization results, the breakup length and droplet diameter were measured by image processing. The experimental data were scaled with ambient Weber number. When the Weber number was smaller than 1, the droplet diameter was close to the nozzle diameter, and distribution of droplet size was not observed. When the Weber number exceeded 1, the breakup length became longer and the generated droplet diameter possessed a distribution with two peaks due to satellite droplet formation. In both cases, the droplet formed at the leading edge of jet. In case that Weber number is around 100, the droplets were formed by entrainment of interfacial wave at jet side. From the mass median diameter data, we can see that the increase of the Weber number caused the decrease of median diameter and the increase of the width of the distribution.

scholarly journals Lattice Boltzmann simulation of liquid falling on horizontal rectangular pillar arrays

2021 ◽  
Vol 321 ◽  
pp. 01014
Author(s):  
Makoto Sugimoto ◽  
Tatsuya Miyazaki ◽  
Zelin Li ◽  
Masayuki Kaneda ◽  
Kazuhiko Suga
Keyword(s):  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Phase Field Model ◽  
Flow Simulation ◽  
High Viscosity ◽  
Two Phase ◽  
Lattice Boltzmann Simulation ◽  
Pillar Arrays ◽  
Boltzmann Method ◽  
Behavior Characteristic

Stator coils of automobiles in operation generate heat and are cooled by a coolant poured from above. Since the behavior characteristic of the coolant poured on the coils is not clarified yet due to its complexity, the three-dimensional two-phase flow simulation is conducted. In this study, as a steppingstone to the simulation of the liquid falling on the actual coils, the coils are modelled with horizontal rectangular pillar arrays whose governing parameters can be easily changed. The two-phase flows are simulated using the lattice Boltzmann method and the phase-field model, and the effects of the governing parameters, such as the physical properties of the cooling liquid, the wettability, and the gap between the pillars, on the wetting area are investigated. The results show that the oil tends to spread across the pillars because of its high viscosity. Moreover, the liquid spreads quickly when the contact angle is small. In the case that the pillars are stacked, the wetting area of the inner pillars is larger than that of the exposed pillars.

LATTICE BOLTZMANN SIMULATIONS OF DROP–DROP INTERACTIONS IN TWO-PHASE FLOWS

2005 ◽  
Vol 16 (01) ◽  
pp. 25-44 ◽  
Author(s):  
KANNAN N. PREMNATH ◽  
JOHN ABRAHAM
Keyword(s):  
Shear Flow ◽  
Lattice Boltzmann ◽  
Flow Model ◽  
Numerical Solutions ◽  
Three Dimensional ◽  
Drop Deformation ◽  
Simple Shear Flow ◽  
Two Phase ◽  
Lattice Boltzmann Simulations ◽  
Boltzmann Method

In this paper, three-dimensional computations of drop–drop interactions using the lattice Boltzmann method (LBM) are reported. The LBM multiphase flow model employed is evaluated for single drop problems and binary drop interactions. These include the verification of Laplace–Young relation for static drops, drop oscillations, and drop deformation and breakup in simple shear flow. The results are compared with experimental data, analytical solutions and numerical solutions based on other computational methods, as applicable. Satisfactory agreement is shown. Initial studies of drop–drop interactions involving the head-on collisions of drops in quiescent medium and off-center collision of drops in the presence of ambient shear flow are considered. As expected, coalescence outcome is observed for the range of parameters studied.

scholarly journals Three-Dimensional Lattice Boltzmann Simulation of Two-Phase Flow Containing a Deformable Body with a Viscoelastic Membrane

2011 ◽  
Vol 9 (5) ◽  
pp. 1397-1413 ◽  
Author(s):  
Toshiro Murayama ◽  
Masato Yoshino ◽  
Tetsuo Hirata
Keyword(s):  
Lattice Boltzmann ◽  
Present Method ◽  
Deformable Body ◽  
Finite Thickness ◽  
Three Dimensional ◽  
Spherical Body ◽  
The Body ◽  
Elastic Model ◽  
Two Phase ◽  
Lattice Boltzmann Simulation

AbstractThe lattice Boltzmann method (LBM) with an elastic model is applied to the simulation of two-phase flows containing a deformable body with a viscoelastic membrane. The numerical method is based on the LBM for incompressible two-phase fluid flows with the same density. The body has an internal fluid covered by a viscoelastic membrane of a finite thickness. An elastic model is introduced to the LBM in order to determine the elastic forces acting on the viscoelastic membrane of the body. In the present method, we take account of changes in surface area of the membrane and in total volume of the body as well as shear deformation of the membrane. By using this method, we calculate two problems, the behavior of an initially spherical body under shear flow and the motion of a body with initially spherical or biconcave discoidal shape in square pipe flow. Calculated deformations of the body (the Taylor shape parameter) for various shear rates are in good agreement with other numerical results. Moreover, tank-treading motion, which is a characteristic motion of viscoelastic bodies in shear flows, is simulated by the present method.

scholarly journals Lattice Boltzmann simulations of incompressible liquid–gas systems on partial wetting surfaces

2011 ◽  
Vol 369 (1945) ◽  
pp. 2510-2518 ◽  
Author(s):  
Ching-Hsiang Shih ◽  
Cheng-Long Wu ◽  
Li-Chen Chang ◽  
Chao-An Lin
Keyword(s):  
Lattice Boltzmann ◽  
Density Ratio ◽  
Three Dimensional ◽  
Bond Number ◽  
Two Phase ◽  
Droplet Shape ◽  
Gas Density ◽  
Partial Wetting ◽  
Lattice Boltzmann Simulations ◽  
Large Density Ratio

A three-dimensional Lattice Boltzmann two-phase model capable of dealing with large liquid and gas density ratios and with a partial wetting surface is introduced. This is based on a high density ratio model combined with a partial wetting boundary method. The predicted three-dimensional droplets at different partial wetting conditions at equilibrium are in good agreement with analytical solutions. Despite the large density ratio, the spurious velocity around the interface is not substantial, and is rather insensitive to the examined liquid and gas density and viscosity ratios. The influence of the gravitational force on the droplet shape is also examined through the variations of the Bond number, where the droplet shape migrates from spherical to flattened interface in tandem with the increase of the Bond number. The predicted interfaces under constant Bond number are also validated against measurements with good agreements.

Numerical Simulations on Hydrodynamic Process of Melt Jet Breakup and Fragmentation With the Two-Phase Lattice Boltzmann Method

2018 ◽  
Author(s):  
Shimpei Saito ◽  
Yutaka Abe ◽  
Akiko Kaneko ◽  
Alessandro De Rosis ◽  
Alessio Festuccia ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Lattice Boltzmann ◽  
Present Model ◽  
Three Dimensional ◽  
Lattice Boltzmann Model ◽  
Hydrodynamic Process ◽  
Two Phase ◽  
Jet Breakup ◽  
Boltzmann Method ◽  
Boltzmann Model

Jet breakup and fragmentation are important phenomena to be well understood during a core-disruptive accident of sodium-cooled fast reactors. The three-dimensional two-phase lattice Boltzmann model developed previously by the authors is improved in numerical stability used to simulate the hydrodynamic process of melt jet breakup. Nonorthogonal central moments is successfully introduced into the model. Numerical simulations of FARO-TERMOS experiments demonstrate the enhancements in stability of the present model. The simulations with two types of grid resolutions show the effect of spatial resolution on the results.

LATTICE BOLTZMANN SIMULATION OF VAPOR–LIQUID EQUILIBRIUM ON 3D FINITE LATTICE

2004 ◽  
Vol 15 (03) ◽  
pp. 459-469 ◽  
Author(s):  
GUSZTÁV MAYER ◽  
GÁBOR HÁZI ◽  
ATTILA R. IMRE ◽  
THOMAS KRASKA ◽  
LEONID V. YELASH
Keyword(s):  
Lattice Boltzmann ◽  
Finite Lattice ◽  
Three Dimensional ◽  
Finite Size ◽  
Two Dimensions ◽  
Finite Size Effect ◽  
Lattice Boltzmann Simulation ◽  
Lattice Boltzmann Simulations ◽  
Vapor Liquid Equilibria ◽  
Vapor Liquid

Numerical calculations for three-dimensional vapor–liquid equilibria have been accomplished by lattice Boltzmann simulations. The aim of this investigation is to test the capability of the lattice Boltzmann method in comparison with solutions obtained by the underlying equation of state. As a result we have found a finite-size effect (just like the ones obtained in one and two dimensions) at small lattice sizes for all phase equilibrium properties and related constants such as the critical exponent β. Here, systems with up to 1003 lattice sites are investigated. Reasonable convergence has been obtained from about 323 lattice sites.

Lattice-Boltzmann Simulations of Complex Fluids

1997 ◽  
Vol 08 (04) ◽  
pp. 783-792 ◽  
Author(s):  
G. Gonnella ◽  
E. Orlandini ◽  
J. M. Yeomans
Keyword(s):  
Free Energy ◽  
Fluid Flow ◽  
Phase Separation ◽  
Lattice Boltzmann ◽  
Stokes Equations ◽  
Positive Curvature ◽  
Navier Stokes ◽  
Two Phase ◽  
Lattice Boltzmann Simulation ◽  
Lattice Boltzmann Simulations

We show that by including thermodynamic functions derived from a chosen free energy in a lattice-Boltzmann simulation of fluid flow it is possible to ensure that the fluid relaxes to a well-defined equlilibrium corresponding to the minimum of the input free energy. Two examples are given of phase separation in a binary fluid: bulk two-phase coexistence and a lamellar phase stabilised by a competition between negative surface tension and positive curvature energy. The lattice-Boltzmann framework simulates the Navier–Stokes equations of fluid flow and hence allows investigation of the effects of hydrodynamics on the kinetics of phase separation and on the rheology of the ordered structures.

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