Abstract
In the present work, an improved double-distribution-function thermal lattice Boltzmann method (LBM) is developed for analyzing the effect of viscous heat dissipation and compression work on microscale Rayleigh–Benard convection. In the proposed method a temperature change is introduced into the LB momentum equation in the form of a momentum source to realize the coupling between the momentum and the energy fields; two sets of evolution equations are established, one for the mass and momentum conservation and the other for the total energy that incorporates viscous heat dissipation and compression work. Numerical results show that the effect of viscous heat dissipation and compression work on the temperature distribution, flow distribution, and average Nusselt number at some Rayleigh numbers and aspect ratios is significant.
Highlights
Rayleigh–Bénard convection [1] is a thermally induced flow between two horizontal plates that are heated from below
In order to realize the coupling between the momentum field and energy field, the coupled DDF-TLBM presented in this paper introduces the temperature change into the LB momentum equation in the form of the momentum source Ki, which affects the distribution of flow velocity and density
In order to investigate the effect of viscous heat dissipation and compression work, the coupled DDF-TLBM is applied to two microscale Rayleigh–Bénard convection numerical models, one considering the viscous heat dissipation and compression work and the other not considering the viscous heat dissipation and compression work
Summary
Rayleigh–Bénard convection [1] is a thermally induced flow between two horizontal plates that are heated from below. Much effort has been spent on investigating Rayleigh–Bénard convection. Zhou et al studied the geometric and physical properties of thermal plumes in turbulent Rayleigh–Bénard convection [3]. A high-resolution measurement of the velocity and temperature boundary layers in Rayleigh–Bénard convection was conducted by Sun et al with applying the particle image velocimetry technique [4]. Sharif and Mohammad investigated the natural convection within cavities with different inclination angles and cavity aspect ratios [5]. Kao et al investigated the nonlinear phenomena of two-dimensional (2D) natural convection in enclosed rectangular cavities and systematically examined the relationship
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