Study On CFD Simulation Method Of Indoor Airflow Field Based On Multi Relaxation Time Lattice Boltzmann Method

Studies have shown that about 80% time of human's life was spent in indoor environment,so the indoor air quality is essential for people's health.The poor air quality caused by improper indoor air distribution accounts for about 45% of the total.Therefore,the study of indoor flow field and airflow organization is particularly important.With the rapid development of computer,CFD has been widely used.And CFD has been more and more widely used in HVAC design and analysis.The traditional finite volume method,as the most frequently used numerical method,has been popular for many years.Lattice Boltzmann method has become popular as a new numerical method in the last twenty years.It has been widely used in porous media flow,multiphase flow and magnetohydrodynamics.However,the author finds that its application in the field of indoor airflow simulation is very little.And there are some problems in these studies,including the backward model,the lack of three-dimensional simulation,the lack of non-isothermal simulation and so on.In view of the inadequate application of lattice Boltzmann method in the field of indoor airflow simulation,the author carried out the research in this area.In this paper,the development history,lattice model,multi relaxation time velocity model,multi relaxation time temperature model,boundary condition and turbulence model are systematically introduced.Subsequently,the author uses lattice Boltzmann method to simulate several classical examples in the field of indoor airflow simulation.Combined with each specific example,the author studied the comparison of turbulence models,the choice of lattice size,the method of multiblock,the simulation under strong heat conditions,the comparison of calculation speed and the advantages and disadvantages of the traditional CFD method.The experimental study on strong natural convection of high temperature heat source is carried out,and the applicability of lattice Boltzmann method to strong natural convection is explored.Through a series of simulation examples,the author proves its effectiveness in the field of indoor airflow simulation.The author also gets a lot of practical skills and meaningful conclusions.The conclusions include: 3D simulation results is better than 2D simulation;the choose of grids size must meet the requirements the accuracy and computation speed;the use of mixed grid can effectively reduce the number of grid and speed up the calculation;method for the simulation of strong natural convection is not perfect;the same as large eddy simulation,the calculation speed is faster than the finite volume method.The authors hope that this study will encourage more people to do research in this field and provide them with some convenience.It is hoped that the lattice Boltzmann method will be widely used in the field of indoor airflow simulation.