掺气挑坎、水流佛氏数及坎后空腔负压对空腔积水的影响  

Influences of ramp size,Froude number and bottom cavity pressure on the cavity backwater of an aerator

作　　者：徐一民[1] 赵伟[1] 杨红宣[1] 王海军[1] 沈春颖[1] 

机构地区：[1]昆明理工大学电力工程学院,昆明650051

出　　处：《水力发电学报》2010年第2期15-20,共6页Journal of Hydroelectric Engineering

基　　金：云南省自然科学基金(项目编号:2009ZC015M);昆明理工大学人培基金(项目编号:KKZ3200804047)

摘　　要：掺气减蚀是使泄水建筑物免遭空蚀破坏的重要措施。为提高掺气减蚀效果,应避免掺气空腔出现严重积水,使水流在掺气空腔内充分掺气。影响掺气空腔积水的因素众多且复杂。本文通过本文作者建立的掺气坎射流曲线方程和掺气空腔积水方程,分析计算了掺气坎坎高、挑角、水流佛氏数、空腔负压对射流空腔积水的影响。计算结果表明,在一定范围内增大掺气坎坎高和挑角对减弱掺气空腔积水是有利的;水流佛氏数增大,空腔积水减弱;空腔负压大,则积水严重。研究成果可为掺气坎的设计提供参考。Aerator is an important device to protect high-speed flow release works from cavitation damage. For a bottom aerator of effective air entrainment,serious backwater in the bottom cavity should be avoided,but the factors that affect the backwater are usually complex. This paper analyzes the effects of the height and deflect angel of the ramp,the flow Froude number and the negative cavity pressure,through calculations by using the equations of jet trajectory and backwater established by the authors. This analysis shows that a ramp of greater height or greater deflect angle within a certain range is favorable to backwater control. An increase in Froude number causes a smaller backwater volume,while a lower negative cavity pressure causes a larger volume. These results can be referenced in aerator design.

关 键 词：水力学 掺气坎 空腔负压 空腔积水 

分 类 号：TV131.32[水利工程—水力学及河流动力学]