Author(s): Li Guojing; Dai Guangqing; Yang Qing; Ma Xudong
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Keywords: Eration to prevent cavitation; Lateral enlargement and vertical drop; Hydraulic characteristics; Large eddy simulation; Sub-grid model; VOF
Abstract: In order to study the flow characteristics in hydraulic aeration facilities with sudden lateral enlargement and vertical drop at the mid-gate chamber outlet, the numerical simulation was carried out with large eddy simulation (LES) model and VOF method. The numerical results showed that the reflection flow was formed along the side cavity region when the the length of side cavity region was too short or longer than the bottom cavity region. Water intrusion into bottom cavity region affected the local aeration density. It mainly caused the air entrained the flow that the flow dynamically contacted with the wall. the upper part of the side cavity region was longer than the lower part due to gravity. The size of water-wing become bigger when the side cavity region increased, a large water-wing caused unfavourable flow conditions and decreased aeration density of the flow near side wall.
Year: 2011