Coupled Lattice Boltzmann and Meshless Simulation of Natural Convection in the Presence of Volumetric Radiation

2015 ◽  
Vol 137 (11) ◽  
Author(s):  
Kang Luo ◽  
Qing Ai ◽  
Hong-Liang Yi ◽  
He-Ping Tan
Keyword(s):  
Natural Convection ◽  
Lattice Boltzmann ◽  
Radiative Heat ◽  
Hybrid Approach ◽  
Distribution Functions ◽  
Type Model ◽  
Direct Collocation ◽  
Separate Particle ◽  
Irregular Geometries ◽  
Mls Approximation

In this work, the coupled lattice Boltzmann and direct collocation meshless (LB–DCM) method is introduced to solve the natural convection in the presence of volumetric radiation in irregular geometries. LB–DCM is a hybrid approach based on a common multiscale Boltzmann-type model. Separate particle distribution functions with multirelaxation time (MRT) and lattice Bhatnagar–Gross–Krook (LBGK) models are used to calculate the flow field and the thermal field, respectively. The radiation transfer equation is computed using the meshless method with moving least-squares (MLS) approximation. The LB–DCM code is first validated by the case of coupled convection–radiation flows in a square cavity. Comparisons show that this combined method is accurate and efficient. Then, the coupled convective and radiative heat transfer in two complex geometries are simulated at various parameters, such as eccentricity, Rayleigh number, and convection–radiation parameter. Numerical results show that the LB–DCM combination is a potential technique for the multifield coupling models, especially with the curved boundary.

Lattice Boltzmann simulation of transient natural convection of air in square cavity under a magnetic quadrupole field

2016 ◽  
Vol 26 (8) ◽  
pp. 2441-2461 ◽  
Author(s):  
Nan Xie ◽  
Yihai He ◽  
Ming Yao ◽  
Changwei Jiang
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Natural Convection ◽  
Lattice Boltzmann ◽  
Distribution Functions ◽  
Square Cavity ◽  
Quadrupole Field ◽  
Content Type ◽  
Magnetic Quadrupole ◽  
Magnetic Quadrupole Field

Purpose The purpose of this paper is to apply the lattice Boltzmann method (LBM) with multiple distribution functions model, to simulate transient natural convection of air in a two-dimensional square cavity in the presence of a magnetic quadrupole field, under non-gravitational as well as gravitational conditions. Design/methodology/approach The density-temperature double distribution functions and D2Q9 model of LBM for the momentum and temperature equations are currently employed. Detailed transient structures of the flow and isotherms at unsteady state are obtained and compared for a range of magnetic force numbers from 1 to 100. Characteristics of the natural convection at initial moment, quasi-steady state and steady state are presented in present work. Findings At initial time, effects of the magnetic field and gravity are both relatively limited, but the effects become efficient as time evolves. Bi-cellular flow structures are obtained under non-gravitational condition, while the flow presents a single vortex structure at first under gravitational condition, and then emerges a bi-cellular structure with the increase of magnetic field force number. The average Nusselt number generally increases with the augment of magnetic field intensity. Practical implications This paper will be useful in the researches on crystal material and protein growth, oxygen concentration sensor, enhancement or suppression of the heat transfer in micro-electronics and micro-processing technology, etc. Originality/value The current study extended the application of LBM on the transient natural convective problem of paramagnetic fluids in the presence of an inhomogeneous magnetic field.

Regularized Lattice Boltzmann Simulation of Laminar Natural Convection in Entrance Region of 2D Channels

2013 ◽  
Vol 307 ◽  
pp. 267-270
Author(s):  
Mehaboob Basha ◽  
C.S. Nor Azwadi
Keyword(s):  
Natural Convection ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Distribution Functions ◽  
Entrance Region ◽  
Nusselt Numbers ◽  
Bernoulli’S Equation ◽  
Lattice Boltzmann Simulation ◽  
Laminar Natural Convection ◽  
Nusselt Number Correlation

This paper presents a numerical study of incompressible laminar natural convection in entrance region of two dimensional vertical and inclined channels using regularized lattice Boltzmann Bhatnaghar-Gross-Krook method. Individual distribution functions with lattice types D2Q9 and D2Q5 are considered to solve fluid flow and thermal fields, respectively. Rayleigh number and inclination angle are varied from 10e2 to 10e6 and 0 to 60°, respectively. Distribution functions are introduced to mimic Bernoulli’s equation for calculating pressure at the inlet. Predicted Nusselt numbers are compared with Nusselt numbers correlation. Averaged Nusselt numbers compare well with Nusselt number correlation of Bar-Cohen & Rohsenow.

scholarly journals Computational Performance of Disparate Lattice Boltzmann Scenarios under Unsteady Thermal Convection Flow and Heat Transfer Simulation

Computation ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 65
Author(s):  
Aditya Dewanto Hartono ◽  
Kyuro Sasaki ◽  
Yuichi Sugai ◽  
Ronald Nguele
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Lattice Boltzmann ◽  
Numerical Results ◽  
Convection And Heat Transfer ◽  
Steady State Condition ◽  
Physical Systems ◽  
Flow And Heat Transfer ◽  
Computational Performance

The present work highlights the capacity of disparate lattice Boltzmann strategies in simulating natural convection and heat transfer phenomena during the unsteady period of the flow. Within the framework of Bhatnagar-Gross-Krook collision operator, diverse lattice Boltzmann schemes emerged from two different embodiments of discrete Boltzmann expression and three distinct forcing models. Subsequently, computational performance of disparate lattice Boltzmann strategies was tested upon two different thermo-hydrodynamics configurations, namely the natural convection in a differentially-heated cavity and the Rayleigh-Bènard convection. For the purposes of exhibition and validation, the steady-state conditions of both physical systems were compared with the established numerical results from the classical computational techniques. Excellent agreements were observed for both thermo-hydrodynamics cases. Numerical results of both physical systems demonstrate the existence of considerable discrepancy in the computational characteristics of different lattice Boltzmann strategies during the unsteady period of the simulation. The corresponding disparity diminished gradually as the simulation proceeded towards a steady-state condition, where the computational profiles became almost equivalent. Variation in the discrete lattice Boltzmann expressions was identified as the primary factor that engenders the prevailed heterogeneity in the computational behaviour. Meanwhile, the contribution of distinct forcing models to the emergence of such diversity was found to be inconsequential. The findings of the present study contribute to the ventures to alleviate contemporary issues regarding proper selection of lattice Boltzmann schemes in modelling fluid flow and heat transfer phenomena.

DOMAIN-DECOMPOSITION TECHNIQUE IN LATTICE BOLTZMANN METHOD

2003 ◽  
Vol 17 (01n02) ◽  
pp. 129-133 ◽  
Author(s):  
ZHAOLI GUO ◽  
CHUGUANG ZHENG ◽  
BAOCHANG SHI
Keyword(s):  
Domain Decomposition ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Decomposition Technique ◽  
Irregular Geometries ◽  
2D Flow ◽  
Boltzmann Method

In this paper a domain-decomposition technique is proposed in the framework of the lattice Boltzmann method in order to handle flows in irregular geometries. The 2D flow in a channel with a square or slant branch cavity is simulated based on this technique.

scholarly journals A Multiple-Grid Lattice Boltzmann Method for Natural Convection under Low and High Prandtl Numbers

Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 148
Author(s):  
Seyed Amin Nabavizadeh ◽  
Himel Barua ◽  
Mohsen Eshraghi ◽  
Sergio D. Felicelli
Keyword(s):  
Natural Convection ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Large Scale ◽  
Bgk Model ◽  
Flow Equations ◽  
Wide Range ◽  
Prandtl Numbers ◽  
Boltzmann Method ◽  
Benchmark Solutions

A multi-distribution lattice Boltzmann Bhatnagar–Gross–Krook (BGK) model with a multiple-grid lattice Boltzmann (MGLB) model is proposed to efficiently simulate natural convection over a wide range of Prandtl numbers. In this method, different grid sizes and time steps for heat transfer and fluid flow equations are chosen. The model is validated against natural convection in a square cavity, since extensive benchmark solutions are available for that problem. The proposed method can resolve the computational difficulty in simulating problems with very different time scales, in particular, when using extremely low or high Prandtl numbers. The technique can also enhance computational speed and stability while keeping the simplicity of the BGK method. Compared with the conventional lattice Boltzmann method, the simulation time can be reduced up to one-tenth of the time while maintaining the accuracy in an acceptable range. The proposed model can be extended to other lattice Boltzmann collision models and three-dimensional cases, making it a great candidate for large-scale simulations.

Sign in / Sign up

Export Citation Format

Share Document