某船用汽轮机高压级改型设计及静叶试验

Retrofit of a marine high pressure steam turbine and relevant stator experiment investigation

为提高汽轮机高压级流动效率,对某船用高压汽轮机末三级进行了静叶及子午流道改型设计,通过改变叶栅的气动负荷分布以及子午流道形状来实现机组性能的改善.应用全三维粘性数值模拟分析了改型前后机组性能的变化以及流场的特点.对比数值模拟结果可以发现,改型设计不仅消除了静叶外端壁附面层的分离,同时使得各列静叶吸力面最低压力点后移,从而有效地降低了叶栅二次流损失.最后对改型前后的静叶进行了平面叶栅气动性能试验,试验结果表明改进后的叶型不仅缩短了吸力面出口逆压梯度段的长度,还有效地提高了叶栅攻角适应能力.

In an effort to achieve more efficiency gains of a marine high pressure steam turbine, an optimization de- sign was conducted to improve the aerodynamic performance of the rear three stages in the high pressure steam tur- bine. By utilizing a stator and meridian flow path retrofit, the stator blade load along the blade surface and end-wall profile were modified. Next, a fully 3D numerical simulation was performed to analyze the performance variations and flow field characteristics of the steam turbine unit before and after retrofit. A comparison of the numerical simu- lation results was presented. The shroud boundary layer separation around the stator tip was eliminated after optimi- zation. Simultaneously, the peak suction surface static pressure of the stator was delayed, leading to a more aft loaded distribution. The relevant profile loss and secondary flow loss were also reduced. Lastly, a plane cascade experiment with reference to the stator before and after modification was conducted to analyze the aerodynamic per- formances. The test results show that the negative pressure gradient fragment of the rear suction side was reduced and the blade attack angle adaptability was improved.