基于反方法的高负荷涡轮动叶激波控制

Shock Wave Control in Highly-Loaded Turbine Rotor Blade Using an Inverse Method

关键词:  S1流面  反方法  激波控制  高负荷涡轮

Key words:  S1 stream surface  Inverse method  Shock wave control  Highly-loaded turbine

摘要:

为控制高负荷涡轮叶栅中的激波、改善涡轮叶栅流动状况，针对E3涡轮第二级动叶中间叶高叶型，通过修改叶型吸力面压力分布进行了弱化激波S1流面反方法研究，并基于反设计叶型，对涡轮整级性能进行了三维数值计算分析。S1流面求解器选取MISES程序，应用Mixed模式反方法对叶型表面压力分布进行修改，并在反设计过程中临时“冻结”边界层来提高计算鲁棒性，加速收敛。结果表明，S1流面反设计叶型变薄，喉道位置前移，叶栅通道内激波强度明显削弱，叶型尾迹损失明显降低；涡轮整级环境下，反设计叶型使低背压工况下的等熵效率提高了约0.55%，涡轮出口激波强度显著降低，高效运行区拓宽，变工况性能较原始涡轮得到优化，验证了本文反方法的可行性。

Abstract:

In order to control the shock wave and improve the flow conditions of highly-loaded turbine cascades， an inverse method study on S1 stream surface was conducted to weaken the shock wave strength using the blade profile at the mid-span of the second stage rotor blade of E3 turbine. This was realized by adjusting the pressure distribution on the blade suction side. Meanwhile， three dimensional numerical simulation was carried out to analyze the performance of the turbine stage with the inverse-designed blade. The MISES code was chosen to solve the flow field on S1 stream surface， and the pressure distribution was modified through ‘mixed-inverse’mode. A temporarily ‘frozen’ boundary layer scheme was employed to enhance the robustness and accelerate the convergence of the inverse design process. Results indicated that the blade thickness got thinner and the throat position moved forward compared to the original geometry. The shock wave strength was reduced significantly， as well as the wake loss.?In addition， under the stage environment， compared to the original turbine， the isentropic efficiency at low back pressure condition increased approximately by 0.55% ， and the shock wave intensity at the turbine exit was reduced greatly. The back pressure interval with?high efficiency was extended and the off-design performance was improved. These results verified the feasibility of the developed inverse method.