Technical measure for discontinuous trajectory bucket energy dissipation and sediment prevention at forebay of pumping station
Gao Chuanchang1, Wang Yuchuan2, Shi Liwen3, Liu Wei3, Yang Hongcun3
(1. College of Electric Power, North China University of Water Conservancy and Hydropower, Zhengzhou, Henan 450011, China; 2. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China; 3. Pingyin Tianshan Electrical Irrigation Agency, Jinan, Shandong 250400, China)
Based on hydraulic flow analysis of forebay and field tests before rehabilitation, the turbulent flow pattern in Tianshan first level pumping station was found, which caused intensive vibration and intermittentvibration of pump units. Then the technical measure of discontinuous trajectory bucket energy dissipation and sediment prevention(DTBED ＆ SPTM), which involves discontinuous bottom baffle sills, discontinuous trajectory bucket piers and two pressure plates, was presented. The experimental results afterrehabilitation show that, with the application of the technical measure, flow patterns of forebay and sump, as well as the pump intake condition are significantly improved, velocity distribution of forebay middle section is uniform and turbulent energy is decreased obviously. The flow rate of single pump, the pump efficiency and device efficiency of pumping station are averagely increased 0.14 m3/s, 4.99％ and 3.88％, respectively. The intermittent vibration of pump body is eliminated, and the vibration standard of pump bell mouth intake decreases from intensity stage 4.5to intensity stage 1.8. The sediment depositionof forebay and sump is slowed down, and the sediment removing time is extended from 800 hours before rehabilitation to 1 300 hours after rehabilitation, which proves effective in sediment prevention. The DTBED ＆ SPTM offers a simple yet effective approach to technical rehabilitation of pumping station technological rehabilitation on rivers with high sediment content.
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