前置掺气坎式阶梯溢洪道掺气水深及消能率的计算

Calculation of aerated water depth and energy dissipation rate of a pre-aerator stepped spillway

在前置掺气坎式阶梯溢洪道水力特性、消能特性、掺气效果、抗空蚀特性研究的基础上,运用动量矩方程推导出阶梯溢洪道形成均匀流时的掺气水深和消能率计算公式,建立了不同单宽流量下掺气水深与阶梯尺寸之间的关系以及阶梯尺寸、阶数与消能率的定量关系。研究表明,前置掺气坎式阶梯溢洪道具有掺气量与掺气浓度宜于控制,底部掺气充分,抗空蚀性能优越,消能率高,适宜于大单宽流量溢洪道等显著特点,可作为进一步推广应用阶梯式溢洪道的理论和试验基础。研究成果得到模型试验的验证并应用于实际工程中。

Based on the study of the hydraulic characteristics of the aerated flows, the theoretical calculation of the aerated water depth and the energy dissipation rate is derived by using the momentum equation on the pre-aerator stepped spillway. The relationship of the aerated water depth and the energy dissipation rate with the step sizes can be obtained theoretically through the equation. The calculated results agree well with the experimental date and are applied to the practical projects. The results indicate that the pre-aerator stepped spillway has the advantage of the easy control of the concentration of the aeration near the bottom floor, ensuring the sufficient aerating of the high energy dissipation rate in the bottom area, and suitable for the project with large discharge rate. This study provides the theoretical and experimental basis for the extension of the earlier study of stepped spillway design.