高负荷串列转子叶尖泄漏流动的发展演化机理研究

Due to its effective control of the development of boundary layer, tandem blades have a remarkable edge over conventional blade in terms of aerodynamic loading. Thus it is an important and practical approach to design the highly-loaded compressor. Considering the highly-loaded design characteristic and strong interaction between forward blade and after blade, the tip leakage flow inside tandem blades can be complex. Thus the effect of tip leakage flow inside tandem blades shouldn’t be ignored. Hence, the purpose of the project is to study the evolution of the rotor tip leakage flow in the highly loaded tandem compressor. In this project, some numerical research will be conducted at first to investigate the effect of some parameters, such as the relative position along the circumferential direction, the relative position along the axial direction, and the ratio of the blade loading between the forward blade and after blade. Then some experimental measurements will be conducted on the low-speed large-scale compressor facility to verify the conclusion obtained from the numerical results. The experimental research will include the effect of the relative position along the circumferential direction on the tip leakage flow of the after blade, the effect of the relative position along the axial direction on the tip leakage flow of the front blade, and the effect of the ratio of the blade loading between the forward blade and after blade on the tip leakage flow in the front and the after blade. Finally, based on the experimental results and the numerical results, some possible methods to optimize the internal flow in the tandem blade will be developed.

串列叶片技术作为一种先进气动布局技术，由于其相比于常规叶片具有显著的负荷水平优势，是实现高负荷压气机设计的重要手段。但是，串列叶片自身的高负荷设计特性以及较强的前后排叶片相互作用都将导致串列叶片中的叶尖泄漏流动更复杂，因此，其产生的影响值得关注。本项目就旨在研究高负荷串列转子叶尖泄漏流动的发展演化机制。研究将首先通过数值模拟方法对影响串列转子前后排叶尖泄漏流的主要因素进行分析，寻找各因素对串列转子前后排叶片内叶尖泄漏流动影响的规律。然后借助低速大尺寸压气机实验台对串列转子典型设计参数对叶尖泄漏流动影响的机制展开实验研究，内容主要包括周向相对位置对串列转子后排叶尖泄漏流的影响机制、轴向相对位置对串列转子前排叶尖泄漏流的影响机制、前后排叶片负荷比对串列转子前后排叶尖泄漏流的影响机制。并最终结合数值模拟和实验测量的结果对高负荷串列转子前后排尖部耦合流动的优化途径进行探索。

串列叶片作为一种先进的叶片气动布局形式，是发展高负荷压气机的重要途径之一。为了解决在三维流动层面串列叶片的优化设计问题，本项目针对高负荷串列转子叶尖泄漏流的演化机制展开了研究。首先，为了在压气机级环境下研究串列转子叶尖泄漏流动的发展演化机制，项目组设计了一套基于叶尖切线速度的负荷系数高达0.46的单级低速串列压气机；其次，在北航低速大尺寸压气机试验台上，采用五孔针分区处理方法和旋转单斜热线测量方法对串列转子出口流场进行了测量、采用动态压力传感器对转子机匣静压进行了动态测量、采用自研壁面双丝热线对转子间隙内流场进行了测量，从而最大程度地对串列转子尖部流场进行了还原，并较为清晰地对串列转子尖部流场结构进行了分析；随后，综合利用实验方法以及经过实验校验的数值模拟方法分别研究了前后排叶片负荷比、相对周向位置以及相对轴向位置对串列转子叶尖泄漏流动结构以及由此引起的流动堵塞及流动损失的影响规律；最后，在以上研究的基础上总结出了串列转子尖部最佳流动结构，并给出了基于尖部流动的串列转子前后排叶片最佳相对位置选取准则，为高负荷串列转子端区优化设计提供了重要支撑。