Numerical Simulation And Experiment Research On Air Distribution In Large Space Building

During the design of air conditioning in large space, how to determine the air distribution and the air condition result of different design has been the difficulties to the designers. With the development of computer industry and CFD (Computational Fluid Dynamics), it becomes possible to simulate & predict air distribution, thermal comfort of design system based on CFD technology in large buildings. In this paper, the thermal comfort and air distribution of air conditioning system in large space is res earched by adopting the method of combination CFD numerical simulation and experiment test.We choose a large atrium in Be ijing for the object. This dissertation builds computational models under the stratified air conditioning design schemes according to the real geometry size of the building and the calculative parameter of the air conditioning. And the PHOENICS software is used to realize the three-dimensional simulation of the temperature field and velocity field under the different air distributions and the results of research are applied in the actual engineering. In simulation, k -εturbulent model is employed, and the SIMPLE algorithm is ad opted. When dealing with the boundary condition in the area near the wall, the wall function is adopted. In addition, the evaluation method of air distribution in large atrium is researched.Based on the stratified air conditioning of the summer design, detailed analysis of distribution of air dis tribution un der the stratified a ir c onditioning is given. The temperature field, speed field, and the infl uencing factors are analysised under the model of different cases. In winter design, the effects of the air supply angle, the air supply rate, air supply tem perature difference, air suppl y spacing to influence the thermal environment are discussed. To validate CFD feasibility, experiment test in the large atrium have been done according to testing condition.The research results show that:Firstly, the supplying air velocity affects forming of stable airflow-cutting directly. Only when the supplying air velocity is between 4m /s and 4.5m /s, the stable airflow-cutting can be for med. Therefor e heat convection between unconditioned zone and conditioned zone can be prevented effectively.Secondly, top exhaust ventilation can reduce th e temperature of uncon ditioned zone evidently. So Energy efficient is very effective. However, over exhaust rate can strengthen heat convection between unconditioned zone and conditioned zone. On the contrary, energy is wasted. The suitable exhaust air ratio is 30%.Thirdly, through the simulation and evalua tion of several air distributions, the writer chooses the best project, which provides reference for the designer.Lastly, The CFD m ethod is validated to be credible and can optimize air conditioning design in large space.