scholarly journals Researches on leakage with lubricating oil using a composite multiphase lattice Boltzmann method

2021 ◽  
pp. 135-135
Author(s):  
Yuhan Li ◽  
Minxia Li ◽  
Yusheng Hu ◽  
Jia Xu ◽  
Liping Ren
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Phase Distribution ◽  
Passive Scalar ◽  
Lubricating Oil ◽  
Working Fluid ◽  
Experimental Investigations ◽  
Multiphase Model ◽  
Simulation Results ◽  
Boltzmann Method

In this paper, a novel model to investigate leakage of gaseous working fluid in pressured devices with lubricating oil was created with Lattice Boltzmann method and Shan-Chen multiphase model. A method to adapt actual pressure-density relation into the lattice via a self-adapting timestep and simplify the simulation of compressible fluid was developed. A model to simulate two-phased leakage with lubricating oil was created with a combination of Shan-Chen model and passive scalar model. The model can realize the phase distribution simulation in the leakage field without causing the pressure and the inter-phase interactions to overlap. This model is also able to be combined with other multiphase models. After a group of preliminary tests of the model, the characteristics of phase distribution and leakage were investigated qualitatively. Five types of phase distribution in the simulation results were classified, which are: uniformed distribution, sphered drips, gas channel, blocked channel and slug bubbles. The results of simulations show good conformance with actual leakage patterns. Preliminary discussions about the leakage features are made upon the results. However, these simulation results are only qualitative and cannot show the quantitative features in leakages. More experimental investigations should be carried out to realize correlations to the model.

Study on the Evolution of Nanofluid Droplet Heated on Horizontal Substrate

2009 ◽  
Author(s):  
Yali Guo ◽  
Shengqiang Shen ◽  
Weizhong Li ◽  
R. Bennacer
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Experimental Investigations ◽  
Heated Substrate ◽  
Strong Pinning ◽  
Simulation Results ◽  
Horizontal Substrate ◽  
The Moment ◽  
Boltzmann Method

Based on the moment space, the lattice Boltzmann method is applied to simulate the evolution of nanofluid droplet on a heated substrate. The results show that the evolution of nanofluid droplet experiences pinning, depinning stage and in the end ring stain is obviously found because of the nanoparticles’ strong pinning. The simulation results are compared with the experimental investigations of reference, and good agreements are obtained.

scholarly journals Study on droplet nucleation position and jumping on structured hydrophobic surface using the lattice Boltzmann method

2021 ◽  
pp. 149-149
Author(s):  
Gaojie Liang ◽  
Lijun Liu ◽  
Haiqian Zhao ◽  
Cong Li ◽  
Nandi Zhang
Keyword(s):  
Lattice Boltzmann Method ◽  
Significant Influence ◽  
Lattice Boltzmann ◽  
Hydrophobic Surface ◽  
Numerical Results ◽  
Nucleation Mode ◽  
Droplet Nucleation ◽  
Simulation Results ◽  
The Individual ◽  
Boltzmann Method

In this study, droplet nucleation and jumping on the conical microstructure surface is simulated using the Lattice Boltzmann Method (LBM). The nucleation and jumping laws of the droplet on the surface are summarized. The numerical results suggest that the height and the gap of the conical microstructure exhibit a significant influence on the nucleation position of the droplet. When the ratio of height to the gap of the microstructure(H/D) is small, the droplet tends to nucleate at the bottom of the structure. Otherwise, the droplet tends to nucleate towards the side of the structure. The droplet grown in the side nucleation mode possesses better hydrophobicity than that of the droplet grown in the bottom nucleation mode and the droplet jumping becomes easier. Apart from the coalescence of the droplets jumping out of the surface, jumping of individual droplets may also occur under certain conditions. The ratio of the clearance to the width of the conical microstructure(D/F) depends on the jumping mode of the droplet. The simulation results indicate that when the D/F ratio is greater than 1.2, the coalescence jump of droplets is likely to occur. On the contrary, the individual jump of droplets is easy to occur.

Two-Dimensional Simulations of Turbulent Flow Past a Row of Cylinders using Lattice Boltzmann Method

2017 ◽  
Vol 14 (01) ◽  
pp. 1750002 ◽  
Author(s):  
Yi-Kun Wei ◽  
Xu-Qu Hu
Keyword(s):  
Lattice Boltzmann Method ◽  
Turbulent Flows ◽  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Passive Scalar ◽  
Two Dimensional ◽  
Flow Past ◽  
High Reynolds ◽  
An Array Of Cylinders ◽  
Boltzmann Method

Two-dimensional simulations of channel flow past an array of cylinders are carried out at high Reynolds numbers. Considering the thickness fluctuating effect on the equation of motion, a modified lattice Boltzmann method (LBM) is proposed. Special attention is paid to investigate the thickness fluctuations and vortex shedding mechanisms between 11 cylinders. Results for the velocity and vorticity differences are provided, as well as for the energy density and enstrophy spectra. The numerical results coincide very well with some published experimental data that was obtained by turbulent soap films. The spectra extracted from the velocity and vorticity fields are displayed from simulations, along with the thickness fluctuation spectrum H(k). Our results show that the statistics of thickness fluctuations resemble closely those of a passive scalar in turbulent flows.

scholarly journals Simulation of Natural Convection in a Concentric Hexagonal Annulus Using the Lattice Boltzmann Method Combined with the Smoothed Profile Method

Mathematics ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 1043
Author(s):  
Suresh Alapati
Keyword(s):  
Fluid Flow ◽  
Natural Convection ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Research Work ◽  
Profile Method ◽  
Flow Intensity ◽  
Simulation Results ◽  
Boltzmann Method ◽  
Present Simulation

This research work presents results obtained from the simulation of natural convection inside a concentric hexagonal annulus by using the lattice Boltzmann method (LBM). The fluid flow (pressure and velocity fields) inside the annulus is evaluated by LBM and a finite difference method (FDM) is used to get the temperature filed. The isothermal and no-slip boundary conditions (BC) on the hexagonal edges are treated with a smooth profile method (SPM). At first, for validating the present simulation technique, a standard benchmarking problem of natural convection inside a cold square cavity with a hot circular cylinder is simulated. Later, natural convection simulations inside the hexagonal annulus are carried out for different values of the aspect ratio, AR (ratio of the inner and outer hexagon sizes), and the Rayleigh number, Ra. The simulation results are presented in terms of isotherms (temperature contours), streamlines, temperature, and velocity distributions inside the annulus. The results show that the fluid flow intensity and the size and number of vortex pairs formed inside the annulus strongly depend on AR and Ra values. Based on the concentric isotherms and weak fluid flow intensity at the low Ra, it is observed that the heat transfer inside the annulus is dominated by the conduction mode. However, multiple circulation zones and distorted isotherms are observed at the high Ra due to the strong convective flow. To further access the accuracy and robustness of the present scheme, the present simulation results are compared with the results given by the commercial software, ANSYS-Fluent®. For all combinations of AR and Ra values, the simulation results of streamlines and isotherms patterns, and temperature and velocity distributions inside the annulus are in very good agreement with those of the Fluent software.

scholarly journals Direct numerical simulation of transitional pulsatile stenotic flow using Lattice Boltzmann Method

2015 ◽  
Author(s):  
Kartik Jain
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Direct Numerical Simulations ◽  
Transitional Flow ◽  
Transitional Flows ◽  
Flow Through ◽  
Simulation Results ◽  
Boltzmann Method ◽  
Realistic Geometries

In the present work, I perform direct numerical simulations of pulsatile flow through a 75% eccentric stenosis using the Lattice Boltzmann Method. The stenosis was studied by Varghese et al. (2007b) in a benchmark computation and the goal of this work is to validate the LBM solver Musubi for transitional flows in anatomically realistic geometries. Whereas most of the study reproduces and compares simulation results from Musubi against the benchmark, the latter part quantifies the Kolmogorov micro-scales and discusses the role of space and time resolutions for the simulation of a transitional flow. The LBM results show an excellent agreement with the previously published results thereby increasing confidence on our Musubi solver for the simulation of transitional flows. The aim of this study is not to compare the computational efficiency of the code or the method but only the physics of the flow.

Numerical Investigation on Interfacial Phenomena of Ferrofluid by Lattice Boltzmann Method

2013 ◽  
Author(s):  
Wenning Zhou ◽  
Yuying Yan ◽  
Xiaoping Luo
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Lattice Boltzmann Method ◽  
Numerical Investigation ◽  
Lattice Boltzmann ◽  
Interfacial Phenomena ◽  
Carrier Fluid ◽  
Simulation Results ◽  
Magnetic Strength ◽  
Boltzmann Method

Ferrofluid, also known as magnetic fluid, is a new-type fluid whose property and morphology can be controlled by the external magnetic field. It mainly consists of carrier fluid and suspended magnetic particles (diameter usually 10 nanometers or less). Ferrofluids behave as a smart or functional fluid and has been finding more and more applications in a variety of fields such as electronic packing, mechanical engineering, aerospace, bioengineering, and thermal engineering. It has therefore recently attracted many researchers’ interest. Due to the nanosize particles and complex interactions between the nanoparticles and carrier fluid, it is difficult to get insights into ferrofluid by pure experimental or theoretical study. To fully understand the mechanism of ferrofluid, efficient and robust computational methods for the numerical simulation of their dynamical behavior are constantly in high demand. Several numerical models have been proposed for ferrofluid. Over the last decade, lattice Boltzmann method, a new mesoscopic approach, has emerged as a powerful tool for the numerical investigation of a broad class of complex flow, including multicomponent and multiphase flows. Compared with other numerical methods, lattice Boltzmann method, which is based on kinetic theory, has advantages to deal with the interfacial interactions of multiphase flow in micro/nano scale. In the present study, we present a multicomponent lattice Boltzmann model to simulate ferrofluid. In this model, the interactions between internal and external forces of ferrofluid are considered. To validate the coupling of the magnetic field, the velocity field and the evolution of the interface, the steady-state shape of the ferrofluid droplet is analysed. Then the influence of the external magnetic field on the ferrofluid droplet formation and deformation process is numerically investigated. The parameters affecting the interfacial phenomena of ferrofluid, including the magnetic Bond number and the susceptibility, are discussed in this paper. The change in the droplet size and the magnetic strength is simulated. The simulation results show the ferrofluid droplet size increases with increasing magnetic strength. All the results are also compared with previous numerical or experimental studies. The simulation results presented in this paper indicate that lattice Boltzmann method is a capable method to study complex magnetic fluid phenomena. It is also hoped that the simulation results offer helpful information on controlling ferrofluid in our practical applications.

A Study of Fluid Interfaces and Moving Contact Lines Using the Lattice Boltzmann Method

2013 ◽  
Vol 13 (3) ◽  
pp. 725-740 ◽  
Author(s):  
S. Srivastava ◽  
P. Perlekar ◽  
L. Biferale ◽  
M. Sbragaglia ◽  
J.H. M. ten Thije Boonkkamp ◽  
...  
Keyword(s):  
Boundary Conditions ◽  
Lattice Boltzmann Method ◽  
Contact Line ◽  
Lattice Boltzmann ◽  
Dynamical Behavior ◽  
Pressure Jump ◽  
Multiphase Model ◽  
Moving Contact ◽  
Wall Boundary Conditions ◽  
Boltzmann Method

AbstractWe study the static and dynamical behavior of the contact line between two fluids and a solid plate by means of the Lattice Boltzmann method (LBM). The different fluid phases and their contact with the plate are simulated by means of standard Shan-Chen models. We investigate different regimes and compare the multicomponent vs. the multiphase LBM models near the contact line. A static interface profile is attained with the multiphase model just by balancing the hydrostatic pressure (due to gravity) with a pressure jump at the bottom. In order to study the same problem with the multicomponent case we propose and validate an idea of a body force acting only on one of the two fluid components. In order to reproduce results matching an infinite bath, boundary conditions at the bath side play a key role. We quantitatively compare open and wall boundary conditions and study their influence on the shape of the meniscus against static and lubrication theory solution.

A Lattice Boltzmann Dynamic Subgrid Model for Lid-Driven Cavity Flow

2004 ◽  
Author(s):  
Fan Yang ◽  
Yulin Wu ◽  
Shuhong Liu
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Cavity Flow ◽  
Driven Cavity ◽  
Subgrid Model ◽  
Benchmark Solution ◽  
Simulation Results ◽  
Driven Cavity Flow ◽  
High Reynolds ◽  
Boltzmann Method

In recent years, the lattice Boltzmann method (LBM) has developed into an alternative and promising numerical scheme for simulating fluid flows and modeling physics in fluids. In order to proposing lattice Boltzmann method for high Reynolds number fluid flow applications, as well as conforming the value of Smagorinsky coefficient of subgrid model appropriately, a dynamic subgrid turbulence model for lattice Boltzmann method was proposed on the base of dynamic Smagorinsky subgrid model and LBGK model. Then the subgrid LBGK model was used to simulate the two-dimensional driven cavity flow at some high Reynolds numbers. The simulation results including distribution of stream lines, dimensionless velocities distribution, stream function, as well as location of vertex center, were compared with benchmark solution. Both simulation results and benchmark solution are agreed with each other.

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