Steady-State Natural Convection in a Rectangular Cavity Filled with Low Prandtl Number Fluids

1990 ◽  
pp. 82-89
Author(s):  
A. A. Mohamad ◽  
R. Viskanta
Keyword(s):  
Steady State ◽  
Natural Convection ◽  
Prandtl Number ◽  
Rectangular Cavity

scholarly journals Double MRT thermal lattice Boltzmann method for simulating natural convection of low Prandtl number fluids

2016 ◽  
Vol 26 (6) ◽  
pp. 1889-1909 ◽  
Author(s):  
Zheng Li ◽  
Mo Yang ◽  
Yuwen Zhang
Keyword(s):  
Relaxation Time ◽  
Steady State ◽  
Natural Convection ◽  
Rayleigh Number ◽  
Prandtl Number ◽  
Lattice Boltzmann ◽  
Oscillation Period ◽  
Content Type ◽  
Multiple Relaxation Time ◽  
Boltzmann Method

Purpose – The purpose of this paper is to test an efficiency algorithm based on lattice Boltzmann method (LBM) and using it to analyze two-dimensional natural convection with low Prandtl number. Design/methodology/approach – Steady state or oscillatory results are obtained using double multiple-relaxation-time thermal LBM. The velocity and temperature fields are solved using D2Q9 and D2Q5 models, respectively. Findings – With different Rayleigh number, the tested natural convection can either achieve to steady state or oscillatory. With fixed Rayleigh number, lower Prandtl number leads to a weaker convection effect, longer oscillation period and higher oscillation amplitude for the cases reaching oscillatory solutions. At fixed Prandtl number, higher Rayleigh number leads to a more notable convection effect and longer oscillation period. Originality/value – Double multiple-relaxation-time thermal LBM is applied to simulate the low Prandtl number (0.001-0.01) fluid natural convection. Rayleigh number and Prandtl number effects are also investigated when the natural convection results oscillate.

Natural convection flow in an open rectangular cavity with cold sidewalls and constant volumetric heat source

2011 ◽  
Vol 225 (5) ◽  
pp. 1191-1201 ◽  
Author(s):  
M Saleem ◽  
S Asghar ◽  
M A Hossain
Keyword(s):  
Natural Convection ◽  
Rayleigh Number ◽  
Finite Difference ◽  
Heat Source ◽  
Prandtl Number ◽  
Rectangular Cavity ◽  
Maximum Temperature ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Volumetric Heat Source

The transient two-dimensional natural convection flow of Newtonian fluid in an open rectangular cavity has been studied numerically. The flow is induced due to constant internal heat generation. The alternate direct implicit (ADI) finite difference, together with upwind finite-difference scheme and successive over relaxation method, are used to solve the non-dimensional equations numerically. Effects of Rayleigh number, Ra, Prandtl number, Pr, and cavity aspect ratio, A, on the flow patterns and isotherms as well as on the heat transfer rate are studied graphically. The maximum temperature induced due to the constant volumetric heat source is found with the increase in cavity width, and to decrease with the increase in Prandtl number and Rayleigh number. The numerical model employed here is found to be in good agreement with the previous work.

Natural convection in a rectangular cavity with piece-wise heated vertical walls: multiple states, stability and bifurcations

2002 ◽  
Author(s):  
Vladimir Erenburg ◽  
Alexander Gelfgat ◽  
Eliezer Kit ◽  
Pinhas Z. Bar-Yoseph ◽  
Alexander Solan
Keyword(s):  
Natural Convection ◽  
Rectangular Cavity ◽  
Vertical Walls ◽  
Stability And Bifurcations

An Investigation of the Effect of interrupted fin arrangements on the Thermal Performance of a Heat Sink under a Free Convection Condition

2019 ◽  
Vol 7 (1) ◽  
pp. 43-53
Author(s):  
Abbas Jassem Jubear ◽  
Ali Hameed Abd
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Natural Convection ◽  
Thermal Performance ◽  
Heat Sink ◽  
Numerical Study ◽  
Ansys Fluent ◽  
Fluent Software ◽  
Steady State Heat ◽  
Steady State Heat Transfer

The heat sink with vertically rectangular interrupted fins was investigated numerically in a natural convection field, with steady-state heat transfer. A numerical study has been conducted using ANSYS Fluent software (R16.1) in order to develop a 3-D numerical model.  The dimensions of the fins are (305 mm length, 100 mm width, 17 mm height, and 9.5 mm space between fins. The number of fins used on the surface is eight. In this study, the heat input was used as follows: 20, 40, 60, 80, 100, and 120 watts. This study focused on interrupted rectangular fins with a different arrangement and angle of the fins. Results show that the addition of interruption in fins in various arrangements will improve the thermal performance of the heat sink, and through the results, a better interruption rate as an equation can be obtained.

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.

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