| Summary: | 碩士 === 國立臺北科技大學 === 冷凍與低溫科技研究所 === 90 === This thesis studies the flow fields and the trajectories of particles in turbulent type clean rooms including a wall-return type, a locally balanced type, and a floor-return type. The dimensions of the numerical models are 7.8m (L) x 7.8m (W) x 2.7m (H). The influences of various factors including supply air velocity, obstacles, particle diameters, and particle injection positions on the flow fields and the trajectories of particles in such clean rooms are studied by numerical simulation based on the so-called standard k —ε two-equation turbulence model. The wall-return type turbulent clean room is less able to exhaust produced particles than the locally balanced type and the floor-return type can. The best effectiveness of ventilation is a floor-return type clean room, the second is a locally balanced type, and the worst is a wall-return type.
Particles generated close to an exhaust air opening are more effectively exhausted from a room. Larger particles (more than 50μm diameter) are hard to be exhausted from a room. The larger velocity (0.70 m/s) and the lower velocity (0.35 m/s) of supply air have no significantly effect on the flow fields. For particles not more than 10μm diameter, both velocities of supply air have little influence on the trajectories of particles. But, for particles more than 50μm diameter, larger velocity of supply air has more escaping particles than lower velocity of supply air.
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