【作者】 梁武科；

【导师】 罗兴锜；

【作者基本信息】 西安理工大学 ， 水力学及河流动力学， 2006， 博士

【摘要】 水轮机转轮是水电机组实现能量转换的核心部件，其性能的优劣对水电机组的运行乃至整个电力系统的生产和安全具有非常重要的意义。因此提高水轮机效率、空蚀性能和稳定性是水轮机研究和设计者的追求目标。在此背景下，本文以水轮机转轮为研究对象，引入计算机辅助几何设计方法和现代优化算法并结合数值模拟进行水轮机转轮的优化设计，同时开展水轮机运行可靠性问题的研究，主要研究内容如下： 1．建立了叶片型面的NURBS参数化表示方法，在此基础上推导出由型值点反求控制点的矩阵形式线性方程组，采用张量积曲面方程将叶片型面转化为空间点阵格式保证了与现行的软件有良好的接口性。基于最小二乘准则延展自由曲面对混流式叶片不完整信息进行了补充，避免叶片实体造型过程中发生畸变。 2．建立了一种叶片制造质量的评价方法。首先通过递归中值滤波器和移动平均法消除由被测表面光洁度、边界完整性等因素引起的测量误差，提高了数据的可靠性。之后采用改进的多步拟和算法对离散曲面测量数据进行了重构，通过与被测曲面的已知数据点进行对比以实现曲面制造质量的评价。 3．针对标准遗传算法的易早熟、收敛速度慢等不足提出了改进方法，并通过测试函数对改进算法的性能进行了评估，将标准遗传算法发展为自适应遗传算法。之后将自适应遗传算法应用于叶栅的多目标优化设计，同时降低了优化对象的水力损失系数和空蚀系数，证明了优化算法的可行性。 4．采用基于CFD的分析技术，对某水电厂水轮机转轮进行了改型设计。并通过模型实验比较改型前后水轮机转轮的各项技术参数指标，结果表明改型后的转轮提高了最优效率，且使高效率区变宽。同时降低了运行区内空蚀系数和压力脉动幅值，达到了预期目标。 5．分析和总结了水电机组振动的故障机理和振动频率特征，探讨了应用小波分析工具对机组振动信号进行消噪处理和故障特征提取的方法，结合国内某电站机组实测振动数据，采用基于D-S证据理论的信息融合方法进行了融合诊断，并根据诊断结果提出了建议措施。更多还原

【Abstract】 The hydraulic turbine runner is the core component of energy conversion of hydropower unit and its performance has important influence on the power unit operation and power grid steady. Improving the effectiveness of hydraulic turbine, cavitations performance and stability always is the goal for the hydraulic turbine researcher and designer. To reach the goal, the runner is designed optimally by CAGD(computer aided geometry design) and modern optimal algorithms and combining the numerical simulation, simultaneously the reliability of the hydropower unit operation is studied. The study mainly has following points:1. NURBS parameterization method of the blade surface is proposed, based on it, the matrix linear equations of solving control point from the data points is derived. The tensor product curved surface equation is applied to transform the blade surface in space point matrix, which has a fine interface to the current software. The free surface is extended and imperfect information of blade is recruited by LMS. The deformation of blade during forming process is avoided.2. The quality valuation method of blade is build. Firstly, the measurement error caused by surface cleanliness and boundary integrality is eliminated by recursion mid-value filter and moving mean method, the data reliability is improved. Secondly, the discrete curved surface measurement data is reconfigured by improved multi-step approximation algorithms, based on it the surface quality evaluation is obtained by comparing the known data point of measured blade surface with reconfigured surface.3. The adaptive GA is developed for the prematurely and slow convergence of standard GA, the performance of modified GA is estimated by test function. The AGA is applied to multiple target optimal design of cascade, which decreases the water head loss coefficient and cavitations coefficient, so the optimal algorithm is viable.4. The redesign of hydraulic turbine runner is carried out based on CFD technology for a certain hydraulic power plant. All the performance data of runners before redesign and after redesign is compared by model experiment. The result shows that the optimized efficiency of remodeling runner is perfectly improved and the high-efficiency band is broaden. At the same time, the cavitations coefficient and pressure fluctuation magnitude is reduced and the expected goal of redesign and optimization is reached.5. The fault mechanism and vibration frequency characteristic of hydropower unit is analyzed and summed up. The method on de-noise and feature extraction of fault signal by wavelet analysis is discussed, according the measurement vibration data of a unit of some hydropower, the fusing diagnosis is made by information fusion method based on D-S evidence theory, the prepositional measure is proposed according to the diagnosis result.更多还原