Application Of Lattice Boltzmann Method In Fluid Flow And Heat Transfer

Lattice Boltzmann method is the mesoscopic method which based on the statistical distribution function and evolution equation. Selecting appropriate discrete velocity model and equilibrium distribution function, the fluid particle move along the established lattice lines as evaluation and collide with the neighboring particles, Then stream along the direction of the discrete velocity. The macroscopic physical parameter, such as density, temperature, velocity and pressure can be obtained via calculating the statistical average of particles properties.In this paper, adopting the lattice Boltzmann method, researched the two-dimensional, three-dimensional porous media flow and heat transfer, two-phase flow, natural convection and conjugate heat transfer deeply. To provide data support and theoretical guidance for more complex engineering problems. The main works of this paper includes:1. Application quartet structure generation set(QSGS) to growth porous medium in the calculation of the area by the theory put forward by M.R Wang. Re-constructors the porous adopt the quartet structure generation set (QSGS), which theory put forward by M.R Wang Mo ran, and grow out porous medium in the calculation area directly. Discussed the difference of the natural porous medium and which re-constructors by QSGS. Studded the flowing properties of porous media based on D2G9 model, and calculated out the flow field distribution inside the porous media. Discussed the relationship between the porosity of the porous medium and iteration time, the influence of different pressure gradients and the porosity to the average velocity, the relationship between permeability and porosity, etc., finally get the mechanism analysis of the flow properties of porous media.2. Studied the two-phase separation of gas-liquid and liquid droplets with the gravity and surface tension along the wall by shen-chen model and developed shan-chen model, obtained the density cloud map and density evolution curve under difference iteration time steps of each other, get the mechanism of two-phase separated from each other.3.Studied natural convection of closed square cavity, Rayleigh-Benard connection and the Representative elementary volume(REV) porous media convection by coupled double distribution function model with appropriate force comes from the outside world. Discussed the effect on convection comes from changing Rayleigh number, and compared with the literatures of average Nusselt number, the result was good in agreement with literatures. As to the multi-scale porous media convection of REV, discussed the Darcy number, porosity and Rayleigh number influence of convection.4. Studied conjugate heat transfer by double distribution function model, obtained the way to made flux and temperature continue at wall boundary. Researched porous media heat transfer based on conjugate heat transfer, discussed the relationship between pressure-gradient and average temperature.