Numerical Simulation of natural convection heat transfer in a annulus at different radius values of inner circular cylinder by using Lattice Boltzmann Method

In the present study, by performing a two-dimensional simulation, the heat transfer from a hot inner circular cylinder to a cold square cavity has been studied and the effect of changing in cylinder radius has been investigated. The 2-D governing equations has beensolved by using the Lattice Boltzmann Method for different radius of cylinder inside a square enclosure with a constant characteristic length for different Rayleigh numbers of 103-106. The results show that the contours of streamlines, isotherms and the averagenusselt number values depend strongly on the Rayleigh number and also ratio of cylinder radius to characteristic length of enclosure (R/L). In this case the vortices created around of the inner circular cylinder. increasing R/L ratio in highest value (R/L=0.3) due to a doublevortices in the eache half of the enclosure. It is observed that increasing the Rayleigh number and R/L ratio, theheat transfer rate from enclosure is also increased. For exlmple, in R/L=0.2, the average nusselt number increases as increasing Rayleigh number from 103-106.

کلیدواژه ها:

Natural convection ، Heat transfer ، Lattice Boltzmann Method ، enclosure