格栅式底流消能工掺气浓度分布规律  

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

作　　者：葛亚飞 邱勇 吴锦钢 周鑫宇 刘毅恒 GE Yafei;QIU Yong;WU Jingang;ZHOU Xinyu;LIU Yiheng(College of Water Resources,Yunnan Agricultural University,Kunming Yunnan 650201,China)

机构地区：[1]云南农业大学水利学院,云南昆明650201

出　　处：《农业工程》2021年第12期65-69,共5页AGRICULTURAL ENGINEERING

摘　　要：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,12水深以下栅前掺气浓度沿高度增加明显,栅后的变化则明显趋缓。②增设格栅后,消力池距离进口5和30 cm位置的栅前掺气浓度值陡增41.11%和26.82%(开孔率34%);格栅开孔率由46%减小到22%,格栅上游侧(6#断面)掺气浓度由37.75%下降到20.32%,格栅下游侧(7#断面)掺气浓度由20.47%下降到8.78%。③增设格栅,栅后近底掺气浓度值(靠近边墙位置)最小也能达到6.06%,并且测点流速不大,意味着包括格栅在内的消力池结构不易发生空蚀破坏。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-holeΓ-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^(3)7.75%to 20.32%,and aeration concentration on downstream side of the grid(section 7)decreased from^(2)0.47%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.

关 键 词：空蚀破坏 开孔率 掺气浓度 水流结构 圆孔Γ形格栅 

分 类 号：TV135[水利工程—水力学及河流动力学]