水轮机尾水管涡带诱发的转轮横向激振力计算

Calculation for transverse force of vibration in turbine runner induced by draft tube surges

针对引起水轮机机组振动最主要的振源——尾水管涡带，建立了一种计算水轮机转轮轴系横向激振力的可行性方法。通过对尾水管涡带对转轮流场影响方式和前人试验、数值结果的调查研究，建立了转轮出口延伸处涡带对转轮内流体的扰动简化模型，将这种涡带扰动流场作用于转轮三维紊流流场计算模型上，最终计算得到了不平衡横向激振力，可以作为轴系分析的已知外力，为水轮机轴系动力分析提供必要的数据。

A feasible calculation method was proposed for the periodical unbalanced transverse force in the francis turbine runner caused by the vortex in the draft tube, which is a chief source of vibration for the hydraulic generator units. Based on the investigation of the incidence on the flow field in the runner by the draft tube surges and the numerical and experimental results from some works by other people, a simplified boundary model was propounded on the exit of the runner which reflects the influence of the vortex. By using this boundary model in the three dimensional turbulent flow computation of turbine, the unbalanced transverse force was solved finally. The result can be used as the external known force, which is the requisite data in the dynamics analysis of turbine axis system.