考虑流体影响的水轮机叶轮固有频率

将工作时水轮机叶轮简化为浸在流体中的旋转圆盘,建立了流体中圆盘振动微分方程,并考虑边界条件对其固有频率的影响.分别研究了不同圆盘转速、不同流体深度以及不同流体密度对固有频率的影响.研究结果表明,与真空中圆盘的固有频率相比,沉浸在流体中的圆盘的固有频率降低.当浸在流体中的圆盘发生旋转时,圆盘的模态由驻波变为行波,不同的旋转方向将对应两个不同的固有频率值.当流体深度减小时,固有频率值降低;流体密度越大,固有频率越小.

Natural Frequency of Turbine Impeller Considering Fluid Effects

The turbine impeller was simplified to a disk immersed in fluid， and the vibration differential equation of the disk was established with considering the effect of boundary conditions on natural frequency of the disk. The influence of different disk speed， fluid depth and fluid density on the natural frequency was studied. The results show that the natural frequency of the disk immersed in fluid decreased comparing with the natural frequency of the disk in vacuum. When the disk in fluid is rotated， the mode of the disk is changed from standing wave to traveling wave. Different rotation directions correspond to two different natural frequencies. As the fluid depth reduces， the value of natural frequency decreases. The higher the fluid density is， the lower the natural frequency is.