长叶片拉金气动影响的数值研究

Numerical Study of Lacing Wires' Aerodynamic Loss Coefficient in Long Blade Cascades

汽轮机末级长叶片常用的拉金形式有圆柱形拉金和椭圆形拉金。由于拉金对气流的阻碍,级内能量损失有一定程度的增加。本文主要运用CFD方法,在同一平面叶栅,对分别装有圆柱形和椭圆形拉金进行了多个工况下气动特性的比较。分析了拉金对叶栅流道气动性能的影响,并且讨论了由两种拉金引起的流动损失在轴向截面上的分布情况。最后,计算了拉金气动损失系数的大小,并与经典经验公式计算值进行了比较。

The form of lacing wires used in the last stage of steam turbines is commonly cylindrical lacing wire or elliptic lacing wire.Because of lacing wires＇ blocking effect,the energy loss in the stage increases.Study on the characteristics of variable condition of the same cascade equipped with a cylindrical or a elliptic lacing wire is made in this paper with CFD.In the results,the performance of the cascades with lacing wires is discussed.It also analyses the loss distribution on the axial cross-section caused by the cylindrical or the elliptic lacing wires in this paper.In tne end,the lacing wires＇ loss coeffient is compared with the previous experimental data.