低负荷和高负荷压气机叶栅气动性能的实验和数值模拟

为了明确采用高负荷设计及一般设计（低负荷）方法的压气机气动性能和流动转捩的差异，进行了不同攻角下的叶栅吸力面流谱绘制和参数测量实验。并基于实验边界条件，采用γ-θ转捩模型开展数值研究。结果表明:与低负荷叶栅相比，随着攻角的增大，高负荷叶栅主流附面层由附着流变为分离流，尾迹的宽度和损失强度增加，并与角区分离融合为一个“带状”损失区。而低负荷叶栅的角区分离仍为紧贴壁面的开式分离，主流附面层仍然附着在壁面上。结果表明:高负荷设计增强了叶栅内逆压力梯度，这使得流动更容易分离，表现为表面形状因子呈现大范围的“峰谷”型分布，转捩模式也由局部旁路转捩变为全叶高范围的分离泡转捩。 

Experiment and numerical simulation on aerodynamic performance of low-loaded and highly-loaded compressor cascades

To clarify the difference in aerodynamic performance and flow transition between compressors using highly-loaded design and general design (low-loaded), the cascade experiments including suction side flow pattern and parameter measurement were performed. Based on the experimental boundary conditions, numerical researches on the suction boundary layer with γ-θ transition model were also conducted. Result showed that, compared with the low-loaded cascade, as the incidence angle increased, the flow boundary layer in highly-loaded cascade transformed from the attached flow to the separated flow, which enhanced wake width and loss and made wake integrate with corner separation loss region into a “strip-shape” loss region. Meanwhile, the flow boundary flow in low-loaded cascade was still an attached flow and the corner separation maintained open separation close to the endwall. The results indicated that highly-loaded design enhanced the inverse pressure gradient in the cascade, causing the flow more easily separated, the surface shape parameter presented a wide range of “peak” distribution, and the transition mode also changed from local bypass transition to all-span separation-induced transition.