The investigation of thermal radiation and free convection heat transfer mechanisms of nanofluid inside a shallow cavity by lattice Boltzmann method

2018 ◽  
Vol 509 ◽  
pp. 515-535 ◽  
Author(s):  
Mohammad Reza Safaei ◽  
Arash Karimipour ◽  
Ali Abdollahi ◽  
Truong Khang Nguyen
2010 ◽  
Vol 133 (2) ◽  
Author(s):  
Mostafa Varmazyar ◽  
Majid Bazargan

During the last decade, a number of numerical computations based on the finite volume approach have been reported, studying various aspects of heat transfer near the critical point. In this paper, a lattice Boltzmann method (LBM) has been developed to simulate laminar free convection heat transfer to a supercritical fluid in a square enclosure. The LBM is an ideal mesoscopic approach to solve nonlinear macroscopic conservation equations due to its simplicity and capability of parallelization. The lattice Boltzmann equation (LBE) represents the minimal form of the Boltzmann kinetic equation. The LBE is a very elegant and simple equation, for a discrete density distribution function, and is the basis of the LBM. For the mass and momentum equations, a LBM is used while the heat equation is solved numerically by a finite volume scheme. In this study, interparticle forces are taken into account for nonideal gases in order to simulate the velocity profile more accurately. The laminar free convection cavity flow has been extensively used as a benchmark test to evaluate the accuracy of the numerical code. It is found that the numerical results of this study are in good agreement with the experimental and numerical results reported in the literature. The results of the LBM-FVM (finite volume method) combination are found to be in excellent agreement with the FVM-FVM combination for the Navier–Stokes and heat transfer equations.


Author(s):  
Majid Bazargan ◽  
Mostafa Varmazyar

During the last decade a number of numerical computations based on the finite volume approach have been reported studying various aspects of heat transfer near the critical point. In this paper, a Lattice Boltzmann Method (LBM) has been developed to simulate laminar free convection heat transfer to a supercritical fluid in a square enclosure. The LBM is an ideal mesoscopic approach to solve nonlinear macroscopic conservation equations due to its simplicity and capability of parallelization. The Lattice Boltzmann Equation (LBE) represents the minimal form of the Boltzmann kinetic equation. The LBE is a very elegant and simple equation, for a discrete density distribution function and is the basis of the LBM. For the mass and momentum equations, an LBM is used while the heat equation is solved numerically by a finite volume scheme. In this study, inter-particle forces are taken into account for non-ideal gases in order to simulate the velocity profile more accurately. The laminar free convection cavity flow has been extensively used as a benchmark test to evaluate the accuracy of the numerical code. It is found that the numerical results of this study are in good agreement with the experimental and numerical results reported in the literature. The results of the LBM–FVM combination are found to be in excellent agreement with the FVM–FVM combination for the Navier-Stokes and heat transfer equations.


2020 ◽  
Vol 30 (12) ◽  
pp. 5017-5035
Author(s):  
Xiaodong Wang ◽  
David Ross

Purpose Natural convection heat transfer during free convection phenomenon in a cavity included with active fins and pipes is investigated. The influence of the orientation of fins on the heat transfer between heat source (i.e. hot fins) and heat sink (i.e. cold pipes) is investigated by using numerical and experimental techniques. Design/methodology/approach For the numerical simulations, the multiple relaxation time (MRT) thermal lattice Boltzmann method (LBM) is used. In this numerical approach, two separated distribution functions are used to solve the flow and temperature distributions within the computational domain. Furthermore, the local/volumetric second law analysis is used to show the impact of evaluated parameters on the heat transfer irreversibility. In addition, the dynamic viscosity and thermal conductivity of TiO2-water nanofluid are measured by using Brookfield viscometer and KD2 pro conductmeter, respectively. Findings The examined range of Rayleigh number is from 103 to 106, and the nanofluid samples are provided in 0, 20, 40, 60, 80 and 100 ppm. Originality/value The originality of this work is use of dual-MRT thermal LBM and experimental measurements of rheological/thermal properties of nanofluid for investigation of free convection problem for the considered application.


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