| Summary: | 碩士 === 國立宜蘭大學 === 生物機電工程學系碩士班 === 104 === The sediment came from the uneaten food and feces. When the sediment accumulates on the bottom of aquacultural ponds, it can cause water quality deterioration. Most of the ponds use paddlewheel to aerate and it cause of circulating flow. This way can let the sediment moving central part of ponds. Then the sediment can eliminate from central sewage pipelines. However, the elimination result is not useful. Only the sediment near the outlet in the center of the pond can be discharged by the daily. This study was to develop a rotary suction pipe for removing pond sediment. The suction pipes were made by PVC pipes. It uses circulating flow to drive. The study used CFD to construct the pond model and flow field. The model and flow field compare with real situation. In the result the flow field was useful to eliminate sediment in orifices size 8,10 mm. In the real situation, let rotary suction pipe rotating speed 0.7 rpm and the orifices size was 10 mm. It is the best result to discharge to sediment.
This study also attempts to enlarge the model. Using Taguchi methods to analysis the impact of orifice size, pond depth, inffluent velocity, inffluent location, pond diameter and pond shape on the flow field and orifice flow rate. The simulation results show that the factors had impact on the sediment removal are orifice size and pond depth. The rotary suction pipe can not be pushed by circulating flow when pond diameter more than 4 m. Therefore, the rotary suction pipe have to install the adjective arm and pontoon.
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