用于扭振分析的叶片模型及参数调整方法

Blade Model for Torsional Vibration Analysis of Turbine-Generator Shafts and the Parameter Adjustment

以某600 MW汽轮发电机组有干摩擦阻尼围带的低压缸末级叶片为对象,研究了叶片在轴系发生扭振时的振动特点,利用有限元模型得到了叶片组的固有特性,并考虑围带对汽轮机长叶片影响,建立了叶片的弹簧-质量块模型,提出此模型的参数调整方法.结果表明:轴系发生扭振时,叶轮振动为无节径的伞形振动;参数调整使得模型的伞型振动计算结果与实际一致,提高了模型精度.

Taking the LP last stage blades in a 600 MW turbine-generator set with dry friction damping shroud as an object of study, vibration characteristics of the blades were researched during torsional vibra- tion of the shafting. Finite element model was used to calculate the inherent characteristics of the blade set, based on which, a spring-mass model of blade was set up for torsional vibration analysis of the shaft- ing, considering the influence of the shroud on the long turbine blades, and subsequently an adjustment method was proposed for the model. Results show that the vibration of bladed disk is of the non nodal um- brella type, when torsional vibration occurs to the shafting system. The adjustment of model parameters makes the umbrella vibration calculation results consist with actual measurements, indicating improved ac- curacy of the model.