| In the current world along with the rapid development of information technology. The manufacturing of VLSI is strict with the cleanliness of clean room more and more. Because the research and optimization of air flow in the clean room is a very effective method to improve the cleanliness. In this thesis, utilizing the technology of computational fluid dynamics (CFD) ,the author simulates the air-flow of a clean room, which has two kinds of air blowing with different ratios of blowing area of filters .And the implementation methods of the optimization of air flow based on simulation result are discussed in detail. At first, the close relationship between the clean room and VLSI is introduced, while the status in quo and trend of development of clean room and CFD in our country and the world are summed up as well. Then the principle of vertical laminar flow clean room and the different styles of blowing are introduced. And the factors of influence of air flow are discussed as follows. In the next place, the K-ε turbulence model cooperated with FVM based on CFD is adopted to simulate a clean room model. And the model is designed with two modes of supply air that are grating penal and the bottom of two sides of the wall, and the flow fields of the clean room under as-built situation are simulated and analyzed. Calculating trough the numerical simulation to this model, we can draw the following conclusions: when the ratio of blowing area is above percent 60, the modes of both the model of grating panel and the model of bottom of two sides of wall have good parallel level of stream. As to the second model, which is air return at the bottom of two sides of wall, the chance of turbulence flow increases with the ratio of blowing area reduces. Therefore, if the ratio is added properly, the air pattern can meet the need of cleanliness level below class 100. At last, the whole thesis is summarized, and the further work of the simulation and adoption of this clean room is pointed out in the end. |
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