In this work, the estimation of crack initiation life of a hydraulic Francis turbine runner is presented. The life prediction is based on the local strain approach to predict the initiation life. First, the analysis i...In this work, the estimation of crack initiation life of a hydraulic Francis turbine runner is presented. The life prediction is based on the local strain approach to predict the initiation life. First, the analysis is carried out in air and in water condition and the runner’s natural frequencies were calculated using the finite element (FE) method. The analysis in air is compared with experimental analysis in order to have a representative model of real runner and subsequently the numerical analysis was perform in water. In the case of the runner immersed in water, the added mass effect due to the fluid structure interaction (FSI) is considered. Second, the static and dynamic stresses were calculated according to life estimation. For the calculation of static stresses, the pressure distribution of water and the centrifugal forces were applied to the runner. The dynamic stresses were estimated for interactions between the guide vane and the runner. Lastly, the estimation of the crack initiation life of the runner was obtained.展开更多
以液压型风力发电机组为研究对象,研究液压型机组低电压穿越控制问题。结合风电机组低电压穿越要求和液压型风力发电机组工作原理,提出一种比例节流阀开口度与变量马达摆角双变量联合控制的低电压穿越的控制方法。建立机组的数学模型,...以液压型风力发电机组为研究对象,研究液压型机组低电压穿越控制问题。结合风电机组低电压穿越要求和液压型风力发电机组工作原理,提出一种比例节流阀开口度与变量马达摆角双变量联合控制的低电压穿越的控制方法。建立机组的数学模型,基于能量耗散原理和动态面控制方法构造低电压穿越双变量控制器。依托30 k VA液压型风力发电机组半物理仿真实验台进行仿真和实验研究,实现了低电压穿越过程中机组液压系统传输功率和输出转速的高精度控制,为液压型机组的低电压穿越控制的进一步研究奠定基础。展开更多
文摘In this work, the estimation of crack initiation life of a hydraulic Francis turbine runner is presented. The life prediction is based on the local strain approach to predict the initiation life. First, the analysis is carried out in air and in water condition and the runner’s natural frequencies were calculated using the finite element (FE) method. The analysis in air is compared with experimental analysis in order to have a representative model of real runner and subsequently the numerical analysis was perform in water. In the case of the runner immersed in water, the added mass effect due to the fluid structure interaction (FSI) is considered. Second, the static and dynamic stresses were calculated according to life estimation. For the calculation of static stresses, the pressure distribution of water and the centrifugal forces were applied to the runner. The dynamic stresses were estimated for interactions between the guide vane and the runner. Lastly, the estimation of the crack initiation life of the runner was obtained.
文摘以液压型风力发电机组为研究对象,研究液压型机组低电压穿越控制问题。结合风电机组低电压穿越要求和液压型风力发电机组工作原理,提出一种比例节流阀开口度与变量马达摆角双变量联合控制的低电压穿越的控制方法。建立机组的数学模型,基于能量耗散原理和动态面控制方法构造低电压穿越双变量控制器。依托30 k VA液压型风力发电机组半物理仿真实验台进行仿真和实验研究,实现了低电压穿越过程中机组液压系统传输功率和输出转速的高精度控制,为液压型机组的低电压穿越控制的进一步研究奠定基础。
