部分进汽对密封间隙流体激振力影响的研究

The Research of the Partial Admission Influence on Seal Clearance Flow Excited Force

针对喷嘴调节汽轮机在调节级出现的部分进汽对密封间隙内流场的影响,参考某型300MW汽轮机高压前轴封结构,建立了数值计算模型,研究了不同的进汽条件下的密封间隙内流场的分布和流体对转子的作用力。结果表明:部分进汽改变了密封间隙内压力和速度分布,在不进汽区域内出现低压区;间隙内的流体会向低压区填充,出现较大的切向速度;流体对转子的作用力会随进汽方式的不同而改变。与调节级动叶间隙激振力共同作用,可对转子运动和轴系的载荷分配产生影响。

To aim at the partial admission influence on the seal flow field near the governing stage of nozzle control steam turbine, a numerical calculation model that base on the structure of a 300MW turbine front shaft seal is set up. The flow field in the seal clearance and force to rotor are analyzed under different partial admission modes. The results show that the partial admission modes have great influence on flow field in the seal clearance. Partial admission can form the prominent low pressure area, increase tangential velocity; moreover, the force that flow to rotor is changed by different partial admission mode. With the force that steam to blade in the control stage, it can change the bearing loading directly. They are all important.