Study Of Solid-To-Fluid Conductivity Ratio Losing Efficacy On The Natural Convection In An Enclosure With The Centered Conducting Body

Lattice Boltzmann method, which developing rapidly since1988, is a systemic mesoscopic method for modeling and simulation. In addition of these advantages:natural parallelism, high calculating efficiency, and a good simulation result, Lattice Boltzmann Method is also very suitable for large-scale parallel calculation, and is an explicit time promoting method. It has successfully used in blood flow, isothermal flow, porous medium flow, heat flow and so on.In the practical engineering application, such as interior architecture, dry material, food baking, etc., the geometric structure is far more complicated than classical natural convection. It is very common that there are several unconnected bodies in an enclosure. The flow field and temperature field can be affected by Rayleigh number (Ra), Prandtl number (Pr), the geometrical characteristics of the conducting body, and solid-fluid conducting ratio. Studies have shown that the heat transfer properties can be affected by solid-to-fluid conducting ratio k(k=ks|kf)and the isotherm can also be changed. Now it isn’t studied that when solid-to-fluid conductivity ratio can have no or little effect with heat transfer (solid-to-fluid conductivity ratio losing efficacy) on natural convection in an enclosure with one centered conducting body or several unconnected conducting bodies.The Lattice Boltzmann Method is used for the study of solid-to-fluid conductivity ratio losing efficacy on the natural convection in an enclosure with one centered conducting body or several unconnected conducting bodies. We use Nusselt number at the left wall to express the natural convection in the enclosure. Over the range0.5≤k≤2.0, which is typical of most (metallic) systems, a corresponding dimensionless parameter D (the width of the conducting body), where Nu number change little, is found with the range105≤Ra≤106. We draw a conclusion that solid-to-fluid conductivity ratio has no or little effect with nature convection in a certain condition.