汽轮机组高背压供热改造轴系振动特性分析

Analysis on Shaft System Vibration Characteristics of Steam Turbine Unit with High Back Pressure Heating Alteration

以国产200MW汽轮机组高背压改造项目轴系为研究目标,细致分析了该类型轴系的结构特点,并基于双转子互换等问题,提出了基于应变能法的轴系离散化方法,建立了更为精确的动力学模型。考虑三支点支承轴系的特殊性,给出适合这类轴系的找中设计理念和方法及计算结果,并进行了对比分析。在此基础上,结合双转子互换情况下高背压改造对低压转子的影响,研究了两组轴系的振动固有特性和响应特性,对各阶临界转速、模态振型、振动幅值、涡动轨迹、轴系变形及轴系稳定性问题进行了全方位研究,深入挖掘200MW汽轮机组高背压改造前后的轴系动力学行为。

In this paper, the shafting system of 200MW high-back pressure retrofit project are studied which are produced in domestic. The structural characteristics are analyzed in detail. Based on double-rotor interchange and other issues, the shaft system discretization method based on the strain energy method is proposed. And a more accurate rotor dynamics model is established. Considering the particularity of the three-pivot bearing shaft system, the design concept, method and calculation result of this design are given, and the comparative analysis is made. On the basis of this, the influence of high back pressure transformation on the low pressure rotor under the condition of double rotor interchange is considered to study the inherent vibration characteristics and response characteristics of the two shaft systems. Dynamical behavior of shaft system before and after alteration of 200MW steam turbine is in-depth mined.