前汽封汽流涡动间歇性振动分析和对策

Analysis and Countermeasures of Intermittent Vibration Induced from Gas Vortex in Front Gas Seal

动态时前轴承座偏移,前汽封内汽封齿间隙不均匀加重,去除氧器蒸汽管线逆止门不严,蒸汽压力不平衡时发生汽流倒灌,前汽封内汽封汽流激振,汽轮机前后轴颈振动数值上升导致联锁跳机。为此对前汽封汽流涡动导致间歇性振动进行探讨和分析,并采取以下措施:汽轮机前座架重新安装摆正,尽可能使前汽封内汽封齿间隙对称均匀;去除氧器逆止门靠近汽轮机本体处加装一个新的逆止门,消除和减少引起前汽封内汽封汽流激振来源;新蒸汽双侧进汽管道纵向方向限位调整;汽轮机发电机组负荷4.2 MW左右时,没有出现前汽封内汽封汽流涡动间歇性振动超差引起的联锁跳机现象。对现场遇到类似间歇性振动问题,提供了分析间歇性振动的思路和应对措施。

Several problems occurred in the performance of one turbine, that are front bearing seat has offset, the gap between inner gas seal teeth become more inhomogeneous, the check valve in steam pipeline for oxygen remover cannot be closed tightly, gas in front gas seal is excited, interlock shut-off is induced from the vibration of front and rear shafts. Thus the discussion and analysis for intermittent vibration induced from the turbulence of gas in front gas seal were carried out, and then the following measures were applied:the front seat frame of the turbine was installed again so as to make the gaps between inner gas seal teeth as homogeneous as possible;a new check valve was added adjacently at the turbine so as to remove the gas excitation source in front gas seal;the axial limits for both two sides of steam inlet pipeline were adjusted. With these measures, interlock shut-off induced from gas turbulence vibration was not occurred when the load of turbine power machine set reached 4.2 MW. What presented in this article may be use as the references for analyzing and solving the problem of intermittent vibration.