基于模态振型分析的大型汽轮机低压转子高速动平衡方法

针对目前传统影响系数法难以平衡某些大型汽轮机低压转子的难题,提出一种基于模态振型分析的大型柔性转子高速动平衡方法。在分析汽轮机转子系统结构的基础上,综合考虑了动平衡机摆架轴承座的动力特性,采用基于有限元的转子轴承动力学分析商业软件DyRoBeS建立了转子-轴承-摆架系统模型,分析转子系统临界转速和振型,从而根据转子的模态振型,结合柔性转子影响系数平衡法要点,设计合理的平衡工艺,有针对性的选择平衡校正面和平衡转速点,采取逐阶次平衡的方法,实现这类大型特殊柔性转子的动平衡。最后以哈汽产的66万千瓦大型汽轮机低压转子高速动平衡试验为例,应用结果表明采用该方法能有效平衡大型柔性转子,且减少了起机次数,节省了平衡费用。

The High-speed Dynamic Balancing Method for Large Steam Turbine Low Pressor Rotor Basedon Modal Shape Analysis

Using the conventional influence coefficient method in the high-speed dynamic balancing machineis usually difficult to balance some large flexible rotors, a new method for large steam turbine LP rotorbalancing based on mode shape analysis was developed in this study. Analyzing of the steam turbine rotorsystem structure with the dynamic characteristics of dynamic balancing machine, the rotor-bearing-pedestalsystem model was established by using DyRoBeS software to get the critical speed and model shape of rotorsystem. Then, a reasonable balance process including balancing planes and speed points was designed basedon model shape combined with influence coefficient method of flexible rotor. The balancing method by ordertime was adopt to meet dynamic balancing requirements of this kind of large special rotor. Finally, a large660MW steam turbine LP-rotor produced by Harbin Turbine Company Limited was taken as an example. Theapplication result shows that the proposed method can balance large flexible rotor effectively, reduce balancingnumber, and save balancing cost.