海流作用下轮机叶轮的屈曲失效分析

Buckling failure analysis of turbine impeller under ocean flow

采用有限元计算方法,全面系统地研究了在海流联合作用下卧式海流轮机叶轮的屈曲失效行为。运用屈曲失效理论、几何力分析、三维数值模拟计算相结合的手段,考虑到轮机叶轮在海流作用过程中产生的内应力作用,分析并讨论了水动力攻角、海流作用力、轮毂对叶轮的支撑点分布位置、叶轮内外压差等参数对叶轮径向屈曲失效的影响。结果表明:海流联合作用时,弦向海流力比纵向海流力的有效推力转换率高68%,相较于传统纯潮流作用下,海流联合作用时的叶轮结构未发生明显屈曲;水动力攻角20°时叶轮抗屈曲能力强,相对径向屈曲形变量比水动力攻角为40°时减小了33%;双支撑点分布位置的变化不会改变轮机叶轮的相对屈曲特性。在双支撑点分布的跨度范围内,叶轮相对径向屈曲较小,叶轮两端翼相对径向屈曲较大;从模拟计算中可以看出,叶轮内外压差变化对叶轮屈曲承载力的影响小。

The finite element method is used to comprehensively and systematically study the buckling failure behavior of the impeller of the vertical axis horizontal inverted hydro-wheel turbine,which undergoes the combined force of ocean flow.This problem is studied by using the combination of buckling failure theory,geometric force analysis,and three-dimensional numerical simulation.In the process of research,the effects of internal stress generated by the turbine impeller during the combined action of the waves are considered.The effects of hydrodynamic angle of attack,wave force,and the position of the support point of the hub on the impeller on the radial buckling failure of the impeller are analyzed and discussed.The results show that compared to the longitudinal flow force,the effective thrust conversion rate of the chord direction flow force is 68%higher when the ocean flow acts on the device together.Compared with the traditional pure tidal current,the impeller structure does not significantly buckle when the ocean tides and waves work together.The impeller has strong anti-buckling capability,when the hydrodynamic attack angle is 20°.Its relative radial buckling deformation is reduced by 33%.The change of the position of the double support points does not change the relative buckling characteristics of the impeller.In the span of the double support point distribution,the impeller has a relatively small radial buckling,but the opposite ends of the impeller have a relatively large radial buckling.It can be seen from the simulation calculation that the variation of the pressure difference between the inside and the outside of the impeller has little effect on the buckling capacity of the impeller.