汽轮机高压胀差超限仿真分析与损伤状态建模评估

Simulation Analysis of High-pressure Differential Expansion Over-limit of Steam Turbine and Its Damage State Assessment Model

汽轮机冷态启动带负荷运行中高压胀差严重超限导致停机,惰走过程中出现剧烈碰摩振动,通过DCS数据调查分析,给出高压胀差大的影响因素。利用ANSYS有限元转子建模,重点模拟了轴封温度变化对高压转子膨胀量影响,提出了机组冷态启动时高压胀差的运行控制措施。基于高压转子外侧端面晃度量,理论估算转子最大弯曲值,采用Matlab建立高压转子集中质量模型,运用Riccati传递矩阵法仿真计算其振型和一阶临界转速区最大振动,判断该高压转子已无法正常投入运行,提出揭缸检查建议。揭缸检查结果验证了转子最大弯曲量等仿真计算结果的准确性。转子建模故障评估对机组检修具有重要指导意义。

The shutdown of steam turbine can be caused by the serious over-limit of the high-pressure differential expansion during the cold start-up and load operation.The unit occurred severe rubbing and vibration in the coasting operation.Through the investigation and analysis of DCS data,the article gives the influence factors of high-pressure differential expansion.With the finite element modeling of rotor in ANSYS,the impact of change of temperature of shaft seal on the expansion increment of high pressure rotor is emphatically simulated.The article gives the operation control measures of the high-pressure differential expansion during the cold start-up of steam turbine.Based on the flutter of the lateral face high-pressure rotor,the maximum bending value of the high-pressure rotor is estimated theoretically;The concentrated mass model of the high-pressure rotor is established with MATLAB.The vibration mode and the maximum vibration in the first critical speed area are calculated by Riccati transfer matrix method.It is diagnosed that the high-pressure rotor could not be operated normally,and suggested to open the cylinder for inspection.The inspection results verified the accuracy of the simulation results induding the maximum bending of the rotor.The assessment model of rotor fault has significant guiding value to the unit maintenance.