格栅式底流消能工掺气浓度分布规律

格栅能够有效改善底流消能效果,减轻或者避免消力池底板发生空蚀破坏.通过水工模型试验,研究圆孔Γ形格栅不同开孔率下栅前、栅后掺气浓度变化.试验结果有以下3个方面.①消力池附壁射流区掺气浓度纵向沿程递减,格栅附近有突变;垂直轴线方向,掺气浓度中部大两侧小,峰值出现位置和入射水股主流位置正相关;竖直方向上,1/2水深以下栅前...

Distribution Law of Aeration Concentration of Grid-type Underflow Energy Dissipater

The grid can effectively improve effect of underflow energy dissipation and reduce or avoid cavitation damage to bottom of stilling pool.Through hydraulic model tests to study changes of air-entrainment concentration before and after the grid under different opening ratios of circular-hole Γ-shaped grid.Test results were as follows.①Aeration concentration in wall jet zone of stilling pool decreased longitudinally，and there was a sudden change near the grid；in vertical axis direction，aeration concentration was large and small in the middle and two sides were small，and peak position was positively correlated with main flow of incident water stream；in vertical direction，aeration concentration below half the water depth increased significantly along the height，and then change became smaller.②With addition of the grid（opening rate 34%），aeration concentration in front of the grid at position 5 and 30 cm away from entrance of stilling pool increased sharply by 41.11% and 26.82%；grid opening rate decreased from 46% to 22%，aeration concentration on upstream side of the grid（section 6）decreased from 37.75% to 20.32%，and aeration concentration on downstream side of the grid（section 7）decreased from 20.47% to 8.78%.③After the grid was added，the minimum aeration concentration value behind the grid（near the side wall）could reach 6.06%，and flow velocity at measuring point was not large，which meant that stilling pool structure including the grid was not easy to occur cavitation damage.