Unsteady RANS Simulation on the Effect of Film Cooling on Entropy Noise Generation in a Two-dimensional Stator Cascade
Unsteady RANS Simulation on the Effect of Film Cooling on Entropy Noise Generation in a Two-dimensional Stator Cascade
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发表时间：
2019-07
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通讯作者：
T. Bach;Y. Mahmoudi;S. Spence
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作者：
T. Bach;Y. Mahmoudi;S. Spence
航空发动机技术的进步降低了喷气和风扇噪声，这增加了燃烧噪声的重要性，也增加了减少熵波动在涡轮级加速时产生的间接噪声的必要性。本文采用非定常RANS模型方法研究了气膜冷却对二维定子叶栅中对流、熵波衰减以及间接熵噪声的影响。首先，对无气膜冷却的轴向涡轮级定子的平均流动特性与米兰理工大学的实验数据进行了比较。然后在静叶的吸力侧和压力侧增加一个单膜冷却孔。结果表明，由于冷却孔的二次流，熵波的幅值减小。然而，由于加速熵波的作用，压力扰动的幅度增大。熵波的衰减和产生的压力波振幅的增大都取决于冷却剂流的质量流量。
Advances in aero engine technology have reduced jet and fan noise, which has increased the significance of combustion noise and the need to reduce the indirect noise generated by entropy fluctuations as they accelerate through the turbine stages. The present work examines the influence of film cooling on the convection and attenuation of entropy wave as well as the indirect entropy noise generated in a two dimensional stator cascade using an unsteady RANS modelling approach. Initially the mean flow properties of the stator are compared with experimental data from the Politecnico di Milano for an axial turbine stage without film cooling. Afterwards a single film cooling hole is added to the suction side and the pressure side of the stator blade. Results show that the amplitude of the entropy wave reduces due to the secondary flow from the cooling holes. However, the amplitude of the pressure perturbation due to the accelerated entropy wave increases. Both the attenuation of the entropy wave and increasing the amplitude of the generated pressure waves depend on the mass flow rate of the coolant flow.