A Computational Model for Adjusting Surface Tension Coefficient in Pseudo-potential Lattice Boltzmann Method

2018 ◽  
pp. 161-170
Author(s):  
Mahmud Ashrafizaadeh ◽  
Seyyed Meysam Khatoonabadi
Keyword(s):  
Surface Tension ◽  
Computational Model ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Surface Tension Coefficient ◽  
Boltzmann Method ◽  
Pseudo Potential

scholarly journals Droplet spreading and permeating on the hybrid-wettability porous substrates: a lattice Boltzmann method study

Open Physics ◽  
2016 ◽  
Vol 14 (1) ◽  
pp. 483-491 ◽  
Author(s):  
Wen-Kai Ge ◽  
Gui Lu ◽  
Xin Xu ◽  
Xiao-Dong Wang
Keyword(s):  
Surface Tension ◽  
Contact Angle ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Droplet Spreading ◽  
Small Surface ◽  
Pore Sizes ◽  
Fluid Properties ◽  
Boltzmann Method ◽  
Porous Substrates

AbstractThe spreading and permeation of droplets on porous substrates is a fundamental process in a variety of applications, such as coating, dyeing, and printing. The spreading and permeating usually occur synchronously but play different roles in the practical applications. The mechanisms of the competition between spreading and permeation is significant but still unclear. A lattice Boltzmann method is used to study the spreading and permeation of droplets on hybrid-wettability porous substrates, with different wettability on the surface and the inside pores. The competition between the spreading and the permeation processes is studied in this work from the effects of the substrate and the fluid properties, including the substrate wettability, the porous parameters, as well as the fluid surface tension and viscosity. The results show that increasing the surfacewettability and the porosity contact angle both inhibit the spreading and the permeation processes. When the inside porosity contact angle is larger than 90° (hydrophobic), the permeation process does not occur. The droplets suspend on substrates with Cassie state. The droplets are more easily to permeate into substrates with a small inside porosity contact angle (hydrophilic), as well as large pore sizes. Otherwise, the droplets are more easily to spread on substrate surfaces with small surface contact angle (hydrophilic) and smaller pore sizes. The competition between droplet spreading and permeation is also related to the fluid properties. The permeation process is enhanced by increasing of surface tension, leading to a smaller droplet lifetime. The goals of this study are to provide methods to manipulate the spreading and permeation separately, which are of practical interest in many industrial applications.

Verification of surface tension in the parallel free surface lattice Boltzmann method in waLBerla

2011 ◽  
Vol 45 (1) ◽  
pp. 177-186 ◽  
Author(s):  
Stefan Donath ◽  
Klaus Mecke ◽  
Swapna Rabha ◽  
Vivek Buwa ◽  
Ulrich Rüde
Keyword(s):  
Surface Tension ◽  
Free Surface ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Surface Lattice ◽  
Boltzmann Method

Analysis of freezing process about falling droplet using the lattice Boltzmann method

2018 ◽  
Vol 28 (10) ◽  
pp. 2442-2462 ◽  
Author(s):  
Xin Zhao ◽  
Bo Dong ◽  
Weizhong Li
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Potential Model ◽  
Horizontal Velocity ◽  
Freezing Process ◽  
Droplet Deformation ◽  
Droplet Shape ◽  
Content Type ◽  
Boltzmann Method ◽  
Pseudo Potential

Purpose The freezing phenomenon of a falling droplet is a frequently encountered phenomenon in various applications, such as spray crystallization, hail formation and artificial snowmaking. Therefore, this paper aims to understand the freezing processes of a falling droplet without and with initial horizontal velocity in a cold space. Design/methodology/approach The freezing processes of a falling droplet were characterized using a modified enthalpy-based lattice Boltzmann method. Findings The temperature field, streamlines and freezing process of the falling droplet were investigated and analyzed. The lower part of the droplet was frozen earlier than the upper part. The freezing trend slowed down in the later stage of the freezing process. The droplet shape was related to the initial vertical velocity, nucleation temperature and initial horizontal velocity. Originality/value A modified enthalpy-based lattice Boltzmann method is proposed. In the model, the improved pseudo-potential model is used and the radiation is considered. This method was firstly used to simulate the freezing process of a falling droplet. By examining these freezing processes in detail, the freezing trend and the effect factors of droplet deformation and freezing time were obtained, respectively.

scholarly journals Simulations of Boiling Systems Using a Lattice Boltzmann Method

2013 ◽  
Vol 13 (3) ◽  
pp. 696-705 ◽  
Author(s):  
L. Biferale ◽  
P. Perlekar ◽  
M. Sbragaglia ◽  
F. Toschi
Keyword(s):  
Numerical Simulations ◽  
Lattice Boltzmann Method ◽  
Latent Heat ◽  
Lattice Boltzmann ◽  
Temperature Fluctuations ◽  
Convective Cell ◽  
Turbulent Convection ◽  
Multi Phase ◽  
Boltzmann Method ◽  
Pseudo Potential

AbstractWe report about a numerical algorithm based on the lattice Boltzmann method and its applications for simulations of turbulent convection in multi-phase flows. We discuss the issue of ’latent heat’ definition using a thermodynamically consistent pseudo-potential on the lattice. We present results of numerical simulations in 3D with and without boiling, showing the distribution of pressure, density and temperature fluctuations inside a convective cell.

Simulation of Droplet Flows Using Lattice Boltzmann Method

2008 ◽  
Author(s):  
Amit Gupta ◽  
Ranganathan Kumar
Keyword(s):  
Surface Tension ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Potential Method ◽  
Time Interval ◽  
Short Time Interval ◽  
Impact Surface ◽  
Spread Factor ◽  
Boltzmann Method ◽  
The Impact

In this work, the mesoscale approach of two-dimensional lattice Boltzmann method (LBM) has been employed to study droplet collision with a dry wall. The impact of drops with solid walls is simulated by using the pseudo-potential method of LBM. Simulations have been conducted for 2<We<162, and it is shown that the maximum spreading of the drop on the solid surface depends on the surrounding density, velocity of impact, surface tension, and the surface wetting characteristics. For a short time interval right after the impact the spreading diameter is shown to follow a parabolic dependence with time. The spread factor is seen to be higher as the Weber number increases. Under certain conditions when the drop has a high impact velocity and/or low surface tension, the kinetic energy of impact dominates over the dissipation and surface energy, leading to breakup of the drop into smaller drops. This breakup is shown to depend upon the wetting/non-wetting nature of the surface used. The spread factor is found to be a maximum at the time of breakup.

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