| Summary: | 碩士 === 國立成功大學 === 水利及海洋工程學系碩博士班 === 92 === Large-scale pumps have been extensively used in sewage treatment plants, flood control pumping stations, and circulating cooling water system of electric power plants. To keep these pumps work efficiently, the flow field in front of the suction pipe must keep uniform and stable. So the design of a sump that is normally defined to be between a forbay and a suction pipe has been a very important issue. Although the geometric design of sump can refer to guidelines which were widely used, ex., the HI Standards and BHRA guidelines, these guidelines are only valid for a simple geometry. In case for complex situations, an evaluation of the preliminary design is still needed through physical modeling tests.
The objectives of present paper are to investigate the pump sump flow fields under different sluice gate submergences and Froude Numbers through physical modeling tests. A 1:10 scale intake model, similar to the circulating water pump in the Shen-Ho Power Plant, was used. Detailed three-dimensional measurements of the approach flow in the pump sump were obtained by using an Acoustic Doppler Velocimeter(ADV). The distributions of mean velocity, velocity standard deviation, and vorticity in the pump sump under difference experimental conditions were discussed. The swirl angles at the throat of the suction pipe were also measured by swirl meter to investigate the influence of different sluice gate submergences and Froude Numbers.
The experimental results show that without sluice gate, the pump-approach flow distributions are uniform. With sluice gate, flow separation occurred behind the sluice gate and transverse vortices formed. The velocity standard deviation and vorticity increase at higher depths. The flow at higher positions becomes the main source of disturbance. As the sluice gate submergence increases, the influenced range of flow enlarged. And vorticity, velocity standard deviation, and swirl angle also increase. As the Froude Number increases, vorticity, velocity standard deviation, and swirl angle also increase. This trend is the same as references mentioned.
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