不同掺气浓度对水垫塘底板荷载影响

发布时间：2018-03-21 20:14

本文选题：水垫塘　切入点：底板壁面　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,我国的水利水电工程建设取得飞速的发展,水利工程的规模一次次的刷新记录,所建设的大坝具有高水头、大流量、窄河谷的泄洪消能特点,水垫塘作为近坝消能的主要形式,其自身在高速水流冲击下的安全性与稳定性,是水垫塘实现消能、防冲的关键性所在。对此,国内外许多学者从工程水力学的理论分析和模型试验方面对水垫塘塘内水动力荷载进行了大量的研究,但是对掺气条件下水垫塘底板的荷载变化情况却研究较少,在高速水流中,掺气减蚀是一种早已被验证,行之有效的减免泄槽空蚀破坏的手段,对高速水流掺气,可以有效的改善负压对泄水建筑物的破坏作用,但掺气浓度对底板壁面脉动压强的影响研究较少。本文以水工模型试验为主,结合理论分析方法,采用数理统计手段,分析掺气浓度对水垫塘底板荷载作用影响。主要研究成果如下:(1)引用紊动冲击射流研究成果,详细的分析了水垫塘内的水流流态特征,并对冲击射流和淹没水跃的典型混合流态进行横向、纵向、水平向水流结构分区。(2)利用数理统计手段,对压力传感器采集的随机数据进行了分析,研究脉动压强的幅值特性、概率密度分布特性、频谱特性。(3)研究了在泄槽段增设掺气坎,对水垫塘塘内水体掺气浓度的影响,分析其沿程变化规律和沿水深的变化规律。(4)详细的研究了不同工况下,分别以入塘流量、塘内水垫深度、掺气浓度为因变量下,脉动压强的幅值、概率密度分布、频谱特性变化情况,归纳其变化规律。
[Abstract]:In recent years, the construction of water conservancy and hydropower projects in China has made rapid development. The scale of water conservancy projects has broken records time after time. The dams built have the characteristics of high water head, large discharge and narrow valley flood discharge and energy dissipation. As the main form of energy dissipation near dam, the safety and stability of water cushion pond under the impact of high speed water flow is the key to the energy dissipation and erosion prevention of water cushion pond. Many scholars at home and abroad have done a great deal of research on hydrodynamic loads in ponds from the aspects of theoretical analysis and model tests of engineering hydraulics, but few researches have been done on the load variation of the bottom slab of submerged ponds under aerated conditions. In high speed flow, aeration erosion reduction is a proven and effective method to reduce cavitation damage in drain channel. Aeration of high speed water flow can effectively improve the damage effect of negative pressure on drain structure. However, the effect of aeration concentration on the fluctuating pressure on the bottom wall is less studied. In this paper, the hydraulic model test is the main method, combined with the theoretical analysis method, the mathematical statistical method is used. This paper analyzes the effect of aeration concentration on the load of the bottom plate of the water cushion pond. The main research results are as follows: 1) the characteristics of the flow pattern in the water cushion pond are analyzed in detail by referring to the research results of turbulent impinging jet. The typical mixed flow patterns of impinging jet and submerged water jump are analyzed by means of mathematical statistics, and the amplitude characteristics of pulsating pressure intensity are studied. Probability density distribution characteristics, spectrum characteristics. (3) the effect of aerating sill on aeration concentration of water body in pond is studied in detail, and the variation law along the course and depth of water is analyzed. (4) in different working conditions, the effect of aeration on aeration concentration is studied in detail. The amplitude of pulsating pressure, the distribution of probability density and the variation of spectrum characteristics were analyzed under the dependent variables of the flow into the pond, the depth of the water cushion in the pond and the aeration concentration.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TV653

【参考文献】