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利用压气机平面叶栅试验,在大负攻角工况、设计工况和角区失速工况下,研究间隙变化对叶栅气动性能的影响,并分析内部流动变化与气动性能变化的关联。试验结果表明,不同工况下间隙变化对流场结构的影响不同,因而对叶栅性能的影响规律也不同。大负攻角工况下,不同间隙叶栅内在压力面前缘附近都存在一对由端壁向叶展中部发展的分离涡,间隙增大可以使叶栅总损失近似线性减小,并使间隙侧气流折转能力略微提升。设计工况下,无间隙侧吸力面角区存在轻微的角区分离,小间隙(0.2%展长)的引入首先会加剧间隙侧角区分离,当间隙进一步增大时,角区分离消失并形成泄漏涡结构。叶栅总损失随间隙增大呈先增大后减小再增加的趋势,角区分离的消除有助于提高间隙侧气流折转能力。角区失速工况下,间隙的引入可以削弱并移除间隙侧角区失速结构,从而使叶栅总损失下降,并在0.5%展长间隙时达到最小值,同时间隙侧气流折转能力得到增强。当间隙进一步增大时,叶栅损失变化不大。在间隙变化过程中,两侧端部流动结构产生相互影响,使两侧流场性能变化呈相反趋势。通过对比全工况范围内的气动性能,叶栅在选取0.5%展长间隙时整体性能最优。
The influence of the gap on the aerodynamic performance of the cascade was studied under the condition of large negative angle of attack (AEG), design conditions and stall conditions in the angular zone by the compressor plane cascade test. The correlation between the internal flow and the aerodynamic performance was analyzed. The experimental results show that the influence of gap changes on the structure of flow field is different under different working conditions and therefore the law of influence on the performance of cascades is also different. Under the condition of large negative angle of attack, there exists a pair of separation vortices developed from the end wall to the middle of the blade, and the increase of the gap can make the total loss of the cascade decrease approximately linearly and make the gap Side air flow ability to improve slightly. Under the design conditions, there is a slight corner separation in the non-gap side suction surface. The introduction of small gap (0.2% span) firstly aggravates the separation of the corner side of the gap, and when the gap further increases, the corner separation disappears Leakage vortex structure is formed. The total loss of cascade increases with the increase of clearance firstly, then decreases and then increases. The elimination of separation in the corner zone helps to improve the folding ability of the side air flow. Under the stall condition, the introduction of clearance can weaken and remove the stall side angular stall structure, so that the total loss of cascade decreases and reaches the minimum value at 0.5% span gap, and the gap side airflow deflecting ability is obtained Enhanced. When the gap increases further, the cascade loss changes little. During the gap change, the flow structures at both ends of the gap interact with each other, causing the opposite trend of the flow field performance on both sides. By comparing the aerodynamic performance over the full working regime, the overall performance of the cascade is best when 0.5% span gap is chosen.