【作者】 何钟宁；

【导师】 王林锁； 陈松山；

【作者基本信息】 扬州大学 ， 水利水电工程， 2007， 硕士

【摘要】 进水流道是大型泵站的一个重要组成部分,其水力特性对水泵性能有着直接的影响。良好的进水条件可以使水泵装置达到良好的运行状态,获得较高的效率。水流流态特别是进水流态直接影响水泵的正常运行。大型轴流泵站,流道相对较短,进水流场不均匀会造成水泵进口流速与压力分布不均匀,极易引起水泵效率下降并产生振动、噪声和空蚀破坏。开展泵站进水流道内流场的研究有助于探求水泵进水流态的变化规律并对复杂几何形状的进水流道优化设计和提高泵站效率及安全可靠性有重要意义。本文的研究分为两部分,一部分是钟形进水流道的数值模拟计算,另一部分是同方案下水工物理模型试验。研究选取对工程造价影响明显且争论较大的流道高度(喇叭管悬空高度)作为对象;文中分别设计了多种方案下的水工物理模型和数值模型。通过深入研究,尝试揭开相关因素对流道性能的影响规律。本文概述了各种典型的进水流道形式,构建了合理的钟形进水流道三维流动数学模型。采用直接求解三维雷诺平均方程和k-ε湍流模型方程组的方法,对钟形进水流道内流场进行三维数值模拟计算。通过数值模拟计算分析研究钟形进水流道进水流态的影响因素,并在此基础上提出合理的悬空高优化水力设计方案。在对钟形进水流道进水流场观测的同时,本文引入两个目标函数-流道出口速度分布均匀度、流速加权平均角度,对数值计算结果进行分析。结果表明钟形进水流道悬空高对水泵叶轮进口断面流态影响较为显著。实验测量得到的结果真实可靠,它是理论分析和数值方法的基础和验证手段。受种种条件制约,有时很难进行所需的实验。在数值模拟计算的基础上,本文进行了物理模型试验。试验主要从流态观测与测试两个方面进行,试验结果表明数值模拟计算结果合理、正确。本文将实验测量和数值模拟相结合,以便两者数据相互验证,并从中发现水泵进水流态的变化规律。本文中进水流道共做了4个水工模型实验方案和6个数值模拟方案。物理模型试验实测了流道的水力损失和部分流态数据。数值模拟中选用了工程实践中最常见的雷诺时均方程和标准k-ε双方程模拟湍流运动、应用有限体积法离散控制方程、SIMPLEC算法求解方程组的方法,最终得到各种方案的模拟计算结果。试验和计算结果表明,钟形进水流道的高度(喇叭管悬空高度)有一合理范围。成果对改进进水流道设计理论和方法,提高运行性能具有重要意义。更多还原

【Abstract】 Intake conduit is an important part of large pumping station, and the hydraulic characteristic of the pumping station inlet has a direct influence on the efficiency of a pump. The efficiency of the pump station can be uprated in the condition of well flow condition. Large axial-flow pumping stations because which have short conduit easily cause bad flow and lead to the efficiency of the pump unit drop and causes vibration, noise, and cavitation erosion. So, the research on the inlet flow pattern of the intake conduit, which contributes to find the flow regulations, have important mearing to optimize the design of the intake conduit with complex geometry and raise the efficiency, safety and reliability of pumping stations.In this paper, the research is divided into two major parts. One is that numerical simulation. The other is the hydraulic model test of the bell-like suction box. The research selects bell-like suction box height (or clearance from floor) as object, because it is influence to the project cost highly and has more disputes. Through the research try to discover the law of relevant factors influence the suction box performance.This paper summarize the different kinds of suction boxes and set up the 3D flow mathematic model of the bell-like suction box. A method based on 3D numerical simulation of the turbulence flow to solve Reynolds-averaged equations and the standard k-εturbulent mode is applied to analyse the flow field in the bell-like suction box. Through the numerical simulation, the factors which affects bell-like suction box flow pattern is analysed and researched, in the light of which the geometrical parameters(bell-like suction box height) of the suction box are hydraulically optimized and the reasonable criteria of the hydraulic design for the suction box are given in this paper. Besides the observation of the flow field in the bell-like suction box, two objective function is applied to analyse the results of numerical simulation. The results show that the main effect of the flow pattern is the bell-like suction box height.The result of measurement is true and reliable. It is basis and verification means of theoretical analysis and numerical simulation. But limited by some conditions, it is very difficult to launch the necessary experiment sometimes. On the foundation of the numerical simulation , this paper make an experimental research on hydraulic model of the bell-like suction box. The experiment is based upon the observation of the flow pattern and the testing of the velocity of flow. The experimental results validate the authenticity of numerical simulation. In this paper, experimental measurements and numerical simulation are combined in order to verified their results and find the flow regulations.In this paper, 4 hydraulic model test schemes and 6 numerical simulation schemes are done about the bell-like suction box. The hydraulic friction (loss of head) and some fluid state data are collected in the hydraulic experiment. In the numerical modeling, based on the Reynolds-averaged equations using the standard k-εdouble model the three dimensional turbulent flow in intake conduit is simulated. Application finite volume method discrete control equations and the SIMPLEC algorithm solve system of equations. Finally computation simulation results about the plans are obtained.The experiment and the computed results indicate that the bell-like suction box height (or clearance from floor) has a reasonable range. Results mean much to improvement of design theories and methods on suction passage and increasement of operation performance.更多还原