轴流转浆式水轮机桨叶的动应力特性

通过对轴流式水轮机全流道内流场进行13个稳定运行工况的非定常流场计算,得到不同工况下转轮桨叶表面非定常水压力载荷,并利用顺序流固耦合方法对桨叶在各种工况下的动应力特性进行计算分析。结果表明:在下游水位下降、机组水头升高时,机组在小功率工况下水力稳定性变差;同时表明机组长期在高水头小功率条件下运行时,由于水压力脉动引起的较大动应力是造成桨叶微裂纹的主要原因。计算结果可为水轮机其他零部件的应力特性及疲劳裂纹分析提供参考。

Dynamic stress characteristics of Kaplan turbine blades

The unsteady flow fields at 13 operating points in a Kaplan turbine were simulated using computational fluid dynamics to obtain the pressure distributions on the runner fluid-solid interfaces.The results were then used in dynamic structural simulations of the Kaplan turbine runner blade at 13 operating points using the fluid-structure interaction method.The results show that the hydraulic unit stability deteriorates at low-power conditions with lower downstream level and increasing heads,and that the major dynamic stresses caused by the pressure fluctuations at high heads and low-power operating points directly lead to runner blade failure.The results provide reference data for the analyses of stress and fatigue in other components of hydraulic turbines.