转子偏心对轴流涡轮气动性能的影响

Influence of Rotor Eccentricity on the Aerodynamic Performance of an Axial Flow Turbine

以Aachen 1.5级轴流亚音速实验涡轮为研究对象,采用商用NUMECA软件包对其转子偏心旋转时的流场进行三维定常模拟。研究在大流量工况下,平均叶顶间隙高度比(平均叶顶间隙高度与叶片高度的比值)分别为0.7%、1.3%、1.9%时转子偏心对涡轮性能的影响。在经过验证与确认的基础上,对结果进行了分析。研究结果表明:转子偏心会减小涡轮进口流量,其影响程度与偏心距和平均叶顶间隙高度有关,偏心距越大变化幅度越大;转子偏心对涡轮等熵效率和总功率的影响与偏心距和平均叶顶间隙高度有关,转子偏心有可能增大等熵效率和总功率,也有可能减小等熵效率和总功率,但其变化幅度随着偏心距的增加而增大。

3D steady numerical simulations on eccentric rotor in Aachen 1.5 axial flow turbine stages are performed with commercial CFD software NUMECA. In order to explore the aerodynamic performance changes of turbomachinery respecting to the eccentric rotor, simulations on three large flow conditions have been performed. The average blade tip clearance height ratio are 0.7%, 1.3% and 1.9%, respectively. The results are analyzed on the basis verification and validation. The results show that the eccentric rotor will reduce turbine inlet flow, the influence is related with eccentricity and average tip clearance height, and the changes increase with the increase of eccentricity; the variation of isentropic efficiency and total power are related with eccentricity and average tip clearance height, eccentric rotor may increase them on some average tip clearance height, and may also reduce them, but the change amplitude with the increase of eccentricity increases.