摘要
为更清楚地认识前置掺气坎阶梯溢洪道近壁面沿程掺气规律,对其掺气特性进行了研究,得到了在不同坡度、单宽流量、台阶体型条件下阶梯竖直面和水平面近壁处掺气浓度沿程分布规律,并与不设前置掺气坎但设置过渡阶梯溢洪道的掺气规律进行了对比分析。研究表明:前置掺气坎式阶梯溢洪道中阶梯水平面与竖直面掺气浓度沿程的分布规律相似,受前置掺气坎的帮助,掺气浓度很高,沿程逐渐减小,达到一定距离后趋于稳定;掺气浓度随单宽流量的增大而减小,随坡度的减缓而减小;前置掺气坎克服了过渡阶梯存在前几级的底部清水区的缺陷,能够用于更大单宽流量。
Pre-aerator stepped spillways, where the aerator is placed prior to the primary step in the stepped spillway, can form a cavity chamber at the bottom to produce enough aeration concentration to avoid the cavitation erosion. To make a better understanding of the bottom aeration characteristics along the pre-aerator stepped spillways, laboratory experiments were carried out, in which aeration concentration distributions on the vertical and horizontal planes along the stepped spillway with different discharges and slopes were investigated. Ulteriorly, comparation of aeration characteristics was made between the pre-aerator stepped spillway and the transitional stepped spillway. It was showed that distribution of aeration concentration on the horizontal surfaces of the pre-aerator stepped spillway was similar to that on the vertical plane. Because of the pre-aerator, the aeration concentration is very high along the primary steps, decreases along the stepped spillways, and tends to the stability for a certain distance. With the increase of discharge per unit width and the decrease of the slope, the aeration concentration decreases. The results indicate that the pre-aerator can eliminate the clear water zone on the bottom of the primary steps, where the transitional steps cannot avoid. Therefore the pre-aerator stepped spillways can be widely used for larger discharges per unit width.
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2014年第3期401-406,共6页
Advances in Water Science
基金
国家自然科学基金资助项目(51109150
51179114)~~
关键词
前置掺气坎
过渡阶梯
阶梯溢洪道
空蚀破坏
掺气浓度
模型试验
pre-aerator
transitional steps
stepped spillway
cavitation erosion
air concentration
model test
