| Summary: | 碩士 === 國立成功大學 === 環境工程學系碩博士班 === 100 === Yun-Lin Offshore Industrial Park is located in the downstream of the Cho-shui River. There are lots of sand will deposit in this area and in the winter, this area’s wind speed often exceed 10m/s. High wind speed and abundant sediment source are the two important factors of wind blow dust. Besides, Yun-Lin Offshore Industrial Park is surrounded by the sea, sea salt can easily enter to the industrial park and the sea salt will speed up rusting. Therefore, wind blow dust and sea salt are the main impact in this region.
The main objective of this research is to design a dust-proof barrier and using CFD model-Fluent to study its collection efficiency of the wind blow dust and the sea salt. By measuring the on-site terrain data of the northwest dike, we can design the overall structure which we want to simulate. After designing the overall structure, the on-site measurement data can be used to setup the Fluent model input parameters, which includes the initial wind speed conditions、dust and sea salt particle size and so forth. In this study, it will simulate many different barriers and find out the optimization design. On-site measurement data includes wind speed and direction、sand sampling and atmospheric suspended particles sampling, which includes TSP、PM10、PM2.5 and MOUDI (Micro-Orifice Uniform Deposition Impactors) . By measuring these data, we could understand not only the sea salt concentration and particle size distribution, but also the sand concentration and particle size distribution.
Learned from the results of on-site measurements during the study period, the wind speed and direction in the northwest dike are mainly influenced by Northeasterly wind, wind direction range are in the north-east to northeasterly winds and the wind speed often exceed 10m/s. Sand sampling analytic data shows that the weight of sand are mainly distributed in the three particle size range, 300 ~ 600 μm、150 ~ 300 μm and 90 ~ 150 μm. Among the three particle size, 150 ~ 300 μm occupies more than 50% weight percentage. On the other hand, the atmospheric suspended particulate sampling reveals that sea salt droplet size distribution is below 10μm, After simulating all the different barriers, we can find out that the best structure design’s total height is recommended to 6 m. The bottom of the best structure is made of solid concrete, and its height is 3 m. The upper of the best structure is made of porous barrier, and its height is 3 m, too. In the simulating results, porosity 0.7 is the optimization design. For wind blow dust, the dust-proof barrier collection efficiency can reach 91.7%, but for sea salt, its collection efficiency is less than 10%. In summary, porous barrier can well defend the wind blow dust, but it can’t effectively defend the sea salt which belongs to the small size particle.
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