温度场对燃气轮机拉杆转子临界转速的影响

Prediction of the Influence of Temperature Field on the Critical Speeds of a Rod-fastened Rotor

对某B型燃气轮机拉杆转子建立整体简化计算模型,在自由-自由支承状态下前三阶固有频率有限元计算值与实物模态测试值误差均小于3.5%,说明用整体模型作动力学分析可行。基于传热学理论,用有限元法求解了该燃机转子的稳态温度场。计及稳态温度场后该燃机前三阶临界转速的计算值均在其对应的运行实测值范围内。文中还给出了B型燃机总支承刚度的取值参考。

With the rod-fastened rotor of a B-type gas turbine considered as a whole,finite element model was established.In the free-free supporting condition,relative errors between the results of the first three natural frequencies calculated and the values measured in modal test are all less than 3.5%,so it is reasonable to study dynamic characteristics based on the existing model.Still,there is a certain difference between the results of the first three critical speeds calculated at normal temperature and the values measured in actual operation.Referring to the theory of heat transfer,steady-state temperature field of the rod-fastened rotor is calculated with the finite element method.Taking steady-state temperature field into account,the results of the first three critical speeds calculated coincide with the values measured well.