Research and Development of Three-Dimensional Controll Diffusion Airfoil

为了开发一种高效率、高喘振裕度的高负荷轴流压气机级技术，设计了一种改善端壁附面层流动的动、静叶片端弯/后掠结构，并通过低速模型试验、内部流动测量和三维Navier-Sotkes数值模拟进行了流动诊断，验证了该结构的有效性。也就是说，采用进口导叶-静叶-转子-静叶模型模拟端壁附面层的发展。对于转子和定子，设计并测试了具有略高载荷的基线叶片和具有与基线叶片相同载荷的端弯/后掠叶片。通过在径向和周向横穿5孔皮托管进行内部流动测量。结论如下：第一，在设计流量下，采用端弯/后掠叶片的动、静叶的效率比采用基准叶片的效率高1.1%。其次，使用端弯/后掠叶片时，转子失速起始点处的喘振裕度增加了19%。第三，通过内流测量，发现端弯/后掠叶片激活了端壁边界层，从而改善了级性能，通过三维N-S分析，发现计算结果解释了端弯/后掠叶片抑制二次流和流动分离的作用。

To develop an advanced technology of highly loaded axial compressor stage with high efficiency and sufficient surge margin, end-bend/swept blades for both rotor and stator, which aim to improve endwall boundary layr flows, were designed and tested, and its effectiveness was verified by low-speed model testing of a stage, internal flow survey and a flow diagnosis by 3D Navier-Sotkes simulation.Test section consists of four cascades, i.e., inlet guide vane-stator-rotor-stator in order to simulate the development of endwall boundary layr. For both rotor and stator, the baseline blades which has slightly high loading and end-bend/swept blades which has the same loading as the baseline blades are designed and tested. Internal flow survey were made by traversing a 5-hole pitot tube in the radial and circumferential direction. Further, the flow field relative to the rotor was measured with a hot wire.Concluded remarks are as follows : Firstly, the efficiency at design flow rate with the use of end-bend/swept blades for both rotor and stator was 1.1 percent higher than with the use of baseline blades. Secondly, the surge margin defined at the rotor stall inception point was 19 percent larger with the use of end-bend/swept blades. Thirdly, from the internal flow survey, it was found that the improvement of stage performance resulted from the activation of endwall boundary layr with the use of end-bend/swept blades.Further, from the 3D Navier-Stokes analysis, it was found that the calculated results explained an effect of the end-bend/swept blades for suppressing a secondary flow and a flow separation.