Simulation of turbulent duct flow by employing shear-improved Smagorinsky model accompanied by forced generalized lattice Boltzmann method

Jafari, Saeed; Rahnama, Mohammad; Javaran, Ebrahim Jahanshahi

doi:10.1108/hff-03-2012-0059

Cited by 2 publications

(2 citation statements)

References 36 publications

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“…We can determine temperature distribution as a function of time in a medium using the Fourier’s law of heat conduction given by: where ρ is density and c is specific heat capacity. We utilize LBM (Demuth et al , 2014; Zhou and Cheng, 2014; Sukop and Thorne, 2005; Mohamad, 2011; Jafari et al , 2013; Rienzo et al , 2011; De et al , 2009) to solve equation (9) under steady state condition (when temperature does not change with time) to obtain a temperature distribution for a medium. Using the temperature distribution, we can estimate the heat flux and the effective thermal conductivity of the medium.…”

Section: Lattice Boltzmann Methodsmentioning

confidence: 99%

Pore scale evaluation of thermal conduction anisotropy in granular porous media using Lattice Boltzmann method

Askari

Ikram

Hejazi

2017

HFF

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Purpose Thermal conduction anisotropy, which is defined by the dependency of thermal conductivity on direction, is an important parameter in many engineering and research studies such as the design of nuclear waste depositional sites. In this context, the authors aim to investigate the effect of grain shape in thermal conduction anisotropy using pore scale modeling that utilizes real shapes of grains, pores and throats to characterize petrophysical properties of a porous medium. Design/methodology/approach The authors generalize the swelling circle approach to generate porous media composed of randomly arranged but regularly oriented elliptical grains at various grain ratios and porosities. Unlike previous studies that use fitting parameters to capture the effect of grain–grain thermal contact resistance, the authors apply roughness to grains’ surface. The authors utilize Lattice Boltzmann method to solve steady state heat conduction through medium. Findings Based on the results, when the temperature field is not parallel to either major or minor axes of grains, the overall heat flux vector makes a “deviation angle” with the temperature field. Deviation angle increases by augmenting the ratio of thermal conductivities of solid to fluid and the aspect ratios of grains. In addition, the authors show that porosity and surface roughness can considerably change the anisotropic properties of a porous medium whose grains are elliptical in shape. Originality/value The authors developed an algorithm for generation of non-circular-based porous medium with a novel approach to include grain surface roughness. In previous studies, the effect of grain contacts has been simulated using fitting parameters, whereas in this work, the authors impose the roughness based on the its fractal geometry.

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Section: Lattice Boltzmann Methodsmentioning

confidence: 99%

Pore scale evaluation of thermal conduction anisotropy in granular porous media using Lattice Boltzmann method

Askari

Ikram

Hejazi

2017

HFF

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“…They compared the results obtained with the LBM to those expected with the finite volume method (FVM). Furthermore, Jafari et al (2013) simulated the flow of a turbulent duct using the generalized lattice Boltzmann equation (GLBE) in which large eddy simulation.…”

Section: Introductionmentioning

confidence: 99%

Lattice Boltzmann modeling of convective flows in a large-scale cavity heated from below by two imposed temperature profiles

Abouricha

Alami

Souhar³

2019

HFF

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Purpose The purpose of this paper is to model the convective flows in a room equipped by a glass door and a heated floor of length l = 0.8 × H and submitted to a sinusoidal temperature profile and mono alternative temperature profile. Design/methodology/approach The paper opts for a numerical study of convective flows in a large scale cavity using the Lattice Boltzmann Method (LBM) by considering a two dimensions (2D) square cavity of side H and filled by air (Pr = 0.71). All the vertical walls, the ceiling and the rest of the floor are thermally insulated, the hot portion of length l = 0.8×H is heated with two imposed temperature profiles of amplitude values 0.2 ≤ a ≤ 0.6 and for two different periods ζ = ζ0 and ζ = 0.4×ζ0. One of the vertical walls has a cold portion θc = 0 that represents the glass door. Findings A systematic study of the flow structure and heat transfer is carried out considering principal control parameters: amplitude “a” and period ζ for Rayleigh number Ra = 108. Effects of these parameters on results are presented in terms of isotherms, streamlines, profiles of velocities, temperature in the cavity, global and local Nusselt number. It has been found that an increase in amplitude or period increases the amplitude of the temperature in the core of cavity. The Nusselt number increases when the amplitude “a” of the imposed temperature increases, but this later is not affected by variation of the period. Originality/value The authors used LBM to simulate the convective flows in a cavity at high Ra, heated from below by tow imposed temperature profiles. Indeed, they simulate a local equipped by a solar water heater (SWH). The floor is subjected to a periodic heating: Sinusoidal heating (Case 1) for which the temperature varies sinusoidally (SWH without a supplement), and mono alternation heating (Case 2), the temperature evolves like a redressed signal (SWH with a supplement). The considered method has been successfully validated and compared with the previous work. The study has been conducted using several control parameters such as the signal amplitude and period in the case of turbulent convection. This allowed us to obtain a considerable set of results that can be used for engineering.

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Simulation of turbulent duct flow by employing shear-improved Smagorinsky model accompanied by forced generalized lattice Boltzmann method

Cited by 2 publications

References 36 publications

Pore scale evaluation of thermal conduction anisotropy in granular porous media using Lattice Boltzmann method

Pore scale evaluation of thermal conduction anisotropy in granular porous media using Lattice Boltzmann method

Lattice Boltzmann modeling of convective flows in a large-scale cavity heated from below by two imposed temperature profiles

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