基于动态应变的水轮机顶盖运行状态测试研究

Research on Test of Hydraulic Turbine Top Cover Running State Based on Dynamic Strain

常规采用磁电式速度传感器测试顶盖振动时,受传感器固有特性和测试工况影响易出现失真,数据不能真实有效反映水轮机顶盖的运行状态。通过振动理论分析和顶盖结构受力计算,明确了激振力、振动与应变三者之间的相关性。以有限元结构分析确定顶盖刚强度的薄弱部位,提出基于该部位的动态应变值作为评价水轮机顶盖运行状态的指标参数,并以稳定运行区域的振动值和动态应变值为基准,建立应变与振动的映射关系,解决顶盖振动测值不准的问题。最后以某电站机组为例,验证了该方法的可行性。

When the magnetoelectric velocity sensor is used to test the vibration of the top cover,distortion is easy to occur due to the inherent characteristics of the sensor and the test conditions,and the data can not truly and effectively reflect the operation state of the water turbine top cover.The correlation among excitation force,vibration and strain was clarified through vibration theoretical analysis and stress calculation of top cover structure.Using finite element structural analysis to determine the weak position of the rigidity and strength of the top cover,the dynamic strain value based on this position was proposed as an indicator parameter for evaluating the operation status of the hydraulic turbine top cover.Based on the vibration value and dynamic strain value in the stable operation area,a mapping relationship between strain and vibration was established to solve the problem of inaccurate vibration measurement of the top cover.Taking a power plant unit as an example,the feasibility of the proposed method was verified.