Recently the air quality has caused people’s great attention, and the appraisal of the air quality has become a hot issue in the world wide. This paper asserts that the age-of-air should be an important index to evaluate the air quality. Since the architecture place becomes more and more complicate and diversity, the traditional searching method has a lot limitations. With the development of computer technique, the superiority of computational fluid dynamics(CFD) method becomes more and more obvious, thus the CFD begins to be applied to the HVAC.
In order to research the distribution of the indoor air draft, this paper sets up a mathematical model of the 2-D indoor air draft’s distribution, applies the CFD to analyze the flow pattern, diffusion properties and the age-of-air. Based on the analysis as above, using the SIMPLE algorithm, this paper works out computer programs to calculate the airflow field and the age-of-air. The programs are applied to simulate the ventilation on the three different types of supplying and exhausting airflow, and the simulation results are analyzed and some useful conclusions are got.