调节级非定常流动与汽流激振力数值研究

摘要

The ANSYS-CFX software was used to numerically study the 3D flow characteristics and excitation force in the control stage of a subcritical 600MW steam turbine under several operating conditions .The results show that partial admission produces excitation force on the moving blades of the control stage .With the opening of the control valve , the outlet pressure and the stage efficiency increase while the enthalpy drop ,stage power and remaining velocity loss decrease . On the admission arc,the excitation force changes smoothly; when moving to the non-admission arc,the excitation force shows a sudden change .Under the two valves fully open condition , the tangential force reaches its peak value and then drops with the opening of the other valves .The frequency concentrate area of the low-frequency force was smaller than 1 000 Hz,which is much smaller than the high-frequency excitation force .%采用ANSYS－CFX商用软件数值研究了亚临界600MW汽轮机调节级在不同工况下的三维非定常流动特性与汽流激振力的变化规律。结果表明：随着调节阀门的开启，调节级后的压力升高，焓降和功率逐渐减小，级效率升高，余速损失减小；部分进汽调节级会对动叶产生明显的激振力；在进汽弧段，动叶激振力变化均匀，而从进汽弧段旋转到非进汽弧段以及在喷嘴端面附近时，汽流激振力会发生很大突变。两阀全开时动叶受切向力最大，随着阀门的开启，叶片受切向力逐渐减小。动叶片受到的低频激振力频率集中区域均小于1000Hz，远小于高频激振力频率。