大功率汽轮机轴系稳定性受喷嘴进汽模式影响的敏感性研究

目前,参与调峰的汽轮发电机组在低负荷下喷嘴组局部进汽弧度更小,其喷嘴配汽模式的选择更加重要。理论上,局部进汽方式下的对角进汽模式是最优选择。实际上,由于机组制造和安装等因素的影响,汽轮机轴系自身的稳定性差异很大,其对喷嘴进汽模式的敏感性是不同的。给出了典型四调节阀汽轮机局部进汽条件下的对角进汽和连续进汽的组合种类,进行了针对性的调节阀组顺序开关测试试验,结果显示:对于轴系稳定性较好的机组,其1号、2号瓦瓦温和轴振对喷嘴进汽模式的变化不敏感,局部进汽条件下对角进汽模式并不是最优的选择方案,侧缸喷嘴组连续进汽模式整体表现较好。该结论可用于指导优化汽轮机运行方式。

Sensitivity Study of High Power Steam Turbine's Shafting Stability Influencedby Nozzle Admission Mode

At present,more and more coal-fired units need flexible peak-adjustment,local steam inlet curve of the nozzle group is smaller under low load.So the choice of safe way of distribution of the nozzle under local steam inlet condition is more important.Theoretically,the diagonal admission mode is the optimal choice for local admission mode.In fact,due to the differences of factors such as manufacturing and installation of turbine shafts,the stability of turbine shafts is sensitive to the nozzle intake pattern.In this paper,first of all,the unbalance steam flow force under the local admission mode of the nozzle of a typical four-high regulating valve is analyzed theoretically.On the basis of the test results of various steam inlet modes,it is found that the stability of the shaft system of the unit is more sensitive to the nozzle intake mode,the diagonal intake mode is not the optimal choice of local steam inlet,and the local continuous steam inlet can also make the operating state of the unit optimal.This is useful to the safe and efficient operation optimization of high power steam turbine.