Numerical Simulation Of Influence Of Air-Current On Indoor Air Quality

Airflow in air-conditioned room has an important influence on the indoor air environment, air quality because it directly affects the temperature, the humidity, the cleaning degree, the cardinal number of temperature, the flow velocity and the energy of air conditioned in room. It is not only an important link for the air conditioned but also is important for the engineering designing. Efficient ventilation and sound air current are significant to improve indoor air quality, control the contamination concentration, and ensure the realization of healthy and comfort air-condition. Limited by lots of facts, the air distribution in room is very difficult to be revealed the distributing law of the flow. In recent years, with the development and application of the computing technology, the level of numerical simulation is higher and higher. So it is available of directly simulating the air distribution with the hydrodynamics, CFD (Computational Fluid Dynamics) has grown a new subject following the development of computer. The thesis use FLUENT software,based on computational fluid mechanics and heat transfer theory, to couple and numerically simulates the flow field and temperature field of four kinds of the forms of air currents in offices. In this paper, four typical ventilation strategies were selected for analyze which are ceiling diffuser with low outlet; grille diffuser with upper outlet on the opposite side; grille diffuser with low outlet on the opposite side; displacement ventilation. This paper is an application of Computational Fluid Dynamics in the turbulent flow of air-conditioned room, Based on the theoretically analysis of physical and mathematical model, the κ ? ε there-equation turbulence model and method of SIMPLE are adopted to simulate the there-dimensional air distribution of air conditioned-room, effect of buoyant force on κ ? ε model is considered and the wall function is used for the boundary condition. Governing equation discrete, solving of the conjugated algebraic set and SIMPLE method are also discussed in this paper. In this paper, two main performances have been done. First, displacement ventilation and mixed ventilation strategies were compared in the round, The results are:When the air inlet velocity of is relatively low, the performance of displacement ventilation in temperature field, contaminants concentration field and thermal comfort are better than the mixing ventilation. Second, the influences of the quantity of contaminants in supply air on their indoor distribution have been studied, the results show that the quantity of contaminants in supply air has large influence on their indoor attribution. At last, through the comparisons and analysis of the results of the numerical simulation of different ventilation strategies, the ways of saving energy and improving the indoor air quality can be found. The results can be used to instruct design of the air current forming, and the aim of comfort and health air-conditioning can be achieved.