Very-Large Eddy Simulations of Disk Heat Transfer in a Rotating Cavity Using Lattice-Boltzmann Method

2018 ◽  
Author(s):  
J. Kouwa ◽  
Y. Iso ◽  
F. Polidoro ◽  
S. Gautier
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Flow Structures ◽  
Physical Parameters ◽  
Transfer Coefficients ◽  
Experimental Heat ◽  
Large Eddy ◽  
Boltzmann Method

Convective heat transfer in the cavity between two corotating disks is of great importance for turbomachinery applications. The complex three dimensional and unsteady flow structures induced by the Coriolis forces inside the cavity, and therefore the resulting heat transfer, are challenging to be measured in an experiment or predicted by simulation. In this paper a simplified cavity geometry, characterized experimentally by Long at al., has been chosen. The results obtained with a Very Large Eddy Simulation using Lattice-Boltzmann Method for two operating point with different rotation speeds are compared to the experimental heat transfer coefficients at the wall. The simulation results show the characteristic flow structures and behavior induced by the different regimes. A sensitivity analysis of the results is presented, both for numerical parameters such as grid resolution and for physical parameters, namely the throughflow velocity profile and shroud temperature.

Lattice Boltzmann simulation of 3D natural convection in a cuboid filled with KKL-model predicted nanofluid using Dual-MRT model

2019 ◽  
Vol 29 (1) ◽  
pp. 365-387 ◽  
Author(s):  
Alireza Rahimi ◽  
Abbas Kasaeipoor ◽  
Emad Hasani Malekshah ◽  
Mohammad Mehdi Rashidi ◽  
Abimanyu Purusothaman
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Lattice Boltzmann Method ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Three Dimensional ◽  
Local Heat Transfer ◽  
Content Type ◽  
Boltzmann Method

Purpose This study aims to investigate the three-dimensional natural convection and entropy generation in a cuboid enclosure filled with CuO-water nanofluid. Design/methodology/approach The lattice Boltzmann method is used to solve the problem numerically. Two different multiple relaxation time (MRT) models are used to solve the problem. The D3Q7–MRT model is used to solve the temperature field, and the D3Q19 is used to solve the fluid flow of natural convection within the enclosure. Findings The influences of different Rayleigh numbers (103 < Ra < 106) and solid volume fractions (0 < f < 0.04) on the fluid flow, heat transfer, total entropy generation, local heat transfer irreversibility and local fluid friction irreversibility are presented comprehensively. To predict thermo–physical properties, dynamic viscosity and thermal conductivity, of CuO–water nanofluid, the Koo–Kleinstreuer–Li (KKL) model is applied to consider the effect of Brownian motion on nanofluid properties. Originality/value The originality of this work is to analyze the three-dimensional natural convection and entropy generation using a new numerical approach of dual-MRT-based lattice Boltzmann method.

Flow and heat transfer simulation with a thermal large eddy lattice Boltzmann method in an annular gap with an inner rotating cylinder

2019 ◽  
Vol 30 (02n03) ◽  
pp. 1950013 ◽  
Author(s):  
Maximilian Gaedtke ◽  
Tabitha Hoffmann ◽  
Volkmar Reinhardt ◽  
Gudrun Thäter ◽  
Hermann Nirschl ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Complex Geometry ◽  
Rotational Velocity ◽  
Taylor Vortices ◽  
Small Width ◽  
Wide Range ◽  
Large Eddy ◽  
Boltzmann Method

In this study, a thermal Large Eddy Lattice Boltzmann Method (LBM–LES) is applied to Taylor–Couette flow simulations, allowing detailed analysis of local heat transport over a wide range of Taylor numbers, including resolved transient Taylor vortices. The challenge in thermal management of electric motors is to control the temperature in the air gap between rotor and stator due to the gap’s small width and complex geometry, in which Taylor vortices strongly influence the heat transfer. This thin gap — here simplified by an annulus — is solved for the first time by a Thermal Lattice Boltzmann Method with a Smagorinsky sub-grid model. The influence of the rotational velocity of the inner cylinder with Taylor numbers from 36 to 511 — corresponding to a Reynolds number on the inner cylinder of up to 126[Formula: see text]000 — is numerically investigated. The simulations are validated on the basis of the global Nusselt number, where we find good agreement with a published measurement series, an empirical correlation and Finite Volume simulations using the SST turbulence model. Special attention is paid on predicting the critical Taylor number, which is reproduced almost exactly by Direct Numerical Simulations (DNS) with LBM, whereas LBM–LES slightly overestimates and the SST model further overestimates the occurrence of Taylor vortices.

Numerical Analysis of Flow and Heat Transfer at a Backward-Facing Step With an Obstacle Based on Lattice Boltzmann Method

2016 ◽  
Author(s):  
Insaf Mehrez ◽  
Ramla Gheith ◽  
Fethi Aloui ◽  
Sassi Ben Nasrallah
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Expansion Ratio ◽  
Physical Parameters ◽  
Backward Facing Step ◽  
Flow Problems ◽  
Flow And Heat Transfer ◽  
Recirculation Length ◽  
Boltzmann Method

The Lattice Boltzmann method is actually considered as one of the simplest approach. The flow and heat transfer distribution in a duct containing a backward and an obstacle are studied for different geometric and physical parameters. The LBM is applied to solve the backward-facing step flow problems for an expansion ratio H/h = 2 in rectangular duct and to determine the effect of the obstacle on flow and heat transfer distribution. The obstacle is situated in the bottom wall of the duct. The effect of various obstacle lengths (0.5<h/S<1.5) will be also considered. All this results were observed for a Prandtl number of 0.71 and different range of Reynolds number (1–200). This study showed the instabilities of velocity, recirculation length, temperature and Nusselt number with the obstacle downstream the step. These results were compared to with published experimental.

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