补汽对透平级气动性能和静叶汽封转子动力特性影响的数值模拟
Numerical Investigations for Effect of Supplementary Steam on Aerodynamic Performance of Turbine Stage and Rotordynamics of Stator Seal

为了研究补汽对汽轮机通流部分气动性能和转子动力特性的影响,首先采用数值求解三维RANS方程和k？拨磐牧髂Ｐ偷姆椒？,研究了无补汽和2种补汽工况下补汽对透平级气动性能的影响。在此基础上,以不同补汽工况获得的透平级静叶汽封的进出口气动参数为边界条件,采用多频椭圆涡动模型和动网格技术计算了静叶汽封的非定常气流激振转子动力特性系数。研究结果表明:补汽射流冲击下游静叶栅的叶根区域会造成旋涡流动,导致下游静叶栅的进口气动参数沿周向出现不均匀分布,透平级的气动性能随着补汽量的增加而下降;补汽射流改变了的下游静叶汽封的气动参数,使得预旋比由0？？02逐渐增大为0.06、0.16,进而导致汽封的转子动力特性发生改变。该结果可为补汽对机组气动性能和转子动力特性影响的研究提供参考。
To investigate the influence of supplementary steam on the aerodynamic performance of turbine through flow and rotordynamic characteristics of diaphragm seal, three？？dimensional Reynolds？？Averaged Navier？？Stokes (RANS) and k？拨？ turbulent model are used to analyze the aerodynamic performance of turbine stage without supplementary steam and with two kinds of supplementary steam. The inlet and outlet boundary conditions of the turbine stage stator seal at three kinds of supplementary steam operating conditions were specified according to flow field calculations. The unsteady fluid excitation rotordynamic characteristics of the stator seal were numerical calculated using multi？？frequency elliptical whirling orbit model and dynamic grids. The numerical results show that the supplementary steam jets impacts on the hub regions of the downstream stator blade and results in the vortex flow. This flow behavior leads to the non？？uniform inlet aerodynamic parameters at the entrance of the stator blade. The aerodynamic performance decreases with the increase of the mass flow rate of the supplementary steam. The supplementary steam jet changes the inlet preswirl and aerodynamic parameters of the downstream stator seal. The unsteady fluid excitation force and rotordynamic coefficients of the stator seal also change with the variation of the inlet flow parameters