高负荷压气机静子叶栅角区分离的叶根开槽控制方法及预测研究

Corner separation, which has been identified as an inherent flow feature of the corner formed by the blade suction surface and the endwall, has a great impact on the total pressure ratio, loading, efficiency and operating range of aero-engines, thus restricting the development of high performing ones for the next generation of aero engine. In this project, experimental studies (such as five-hole probe and SPIV) and LES/DDES will be used to investigate corner separation with and without control by setting slot from pressure surface to suction surface of the blade in a high-speed highly-loaded linear compressor cascade. The data base of averaged flow and turbulence flow fields for corner flows will be set up by experimental results and LES/DES results. Physical mechanisms of corner separation development and its control by slotted blade will be analyzed. Turbulence nonequilibrim transport nature and anisotropy in corner flows will be systematically analyzed based on above data base. The correlations between turbulence nonequilibrim transport nature, turbulence anisotropy and time-mean flows will be tried to set up. Based the correlations, an improving method for turbulence models will be proposed, and turbulence models will be improved to take account of the turbulence nonequilibrim transport nature and anisotropy. The improved turbulence models will be validated systematically to make sure that can predict the corner flows in compressor cascade accurately at different operating conditions. At last, the improved model will be used to investigate flow control effect under a series of slot configurations. Then the correlations between slot geometries and flow fields will be tried to set up.. Finally slot design criterion will be proposed and optimized slot configuration to effectively control corner separation can be designed fast. The project will make effort to improve the performance of advanced gas turbine and aero engine.

静子中角区分离对压气机性能有重要影响，制约了高负荷高性能压气机的发展。本申请是针对下一代高负荷静子中的角区分离流动预测和控制开展的基础研究，采用高速高负荷叶栅作为研究对象，结合先进实验测量技术(5孔针、SPIV等)和LES/DDES，研究有无叶根开槽控制两种情况下的角区分离流动。基于实验结果和实验验证过的LES/DDES结果，建立高速高负荷压气机叶栅中丰富的平均流场和湍流场数据库；分析角区分离流动的发生、发展和演化机制，分析叶根开槽控制角区分离的机理；分析湍流特性（如非平衡、各向异性），建立湍流特性和平均流场间的关联，内化湍流特性改进湍流模型，显著提高预测角区分离流动、叶根开槽射流条件下的角区流动的精度；基于改进的湍流模型，开展不同条件下叶根开槽的参数化数值研究，构建槽道参数和流场之间的关联，建立叶根开槽的参数化设计准则。为下一代高负荷静子角区分离流动提供可靠的预测方法和有效的控制方法！

压气机是航空发动机的关键部件，对发动机的性能有重要影响，高效率高负荷压气机设计仍是先进航空发动机设计的技术瓶颈。压气机端壁和叶片吸力面构成的角区内存在着固有的三维分离流动，对压气机的压比、负荷、效率和稳定工作裕度有重要影响，制约了高负荷高性能压气机的发展。因此，在工程设计中需要准确预测及有效控制三维角区分离流动。当前，准确预测和有效控制角区分离仍是一个巨大的挑战，不仅是压气机设计中关注的重点问题，更是内流研究的关键科学问题。.本项目是针对高负荷静子中的角区分离流动预测和控制开展的基础研究，采用高速高负荷叶栅作为研究对象，结合先进实验测量技术和高精度模拟方法（LES/DDES），研究叶片端区开槽控制角区分离流动。主要进展如下：（1）基于实验结果和实验验证过的高精度计算结果，建立了高速高负荷压气机叶栅三维角区分离流动的高精度数据库。（2）角区分离流动湍流机理分析和湍流模型改进研究。针对CA叶栅和PVD叶栅等的高精度计算结果，深入分析了角区分离流动的湍流场特性，校验了常用湍流模型及修正方法的性能；提出了采用螺旋度计及湍流能量反传改进了SST湍流模型（SST-Helicity），显著提高了对多个叶栅（CA叶栅、PVD叶栅和NACA65-k48叶栅）三维角区分离流动的模拟精度。（3）角区分离流动机理及影响机制研究。针对CA叶栅和NACA65-k48叶栅，分析了稠度对角区分离的影响，提出了一种新的叶片吸力面失速的分离形式，揭示了压气机三维角区分离向失速转变的主要物理机制，开展了吸力面端区喉道处“自适应”射流控制角区分离的研究。（4）角区分离流动的叶片端区开槽控制研究。提出了叶片端区开槽控制角区分离的新方法，针对CA叶栅和NACA65-k48叶栅，数值研究了叶片端区开槽对角区的控制效果，进一步实验验证了CA叶栅在0.59马赫数下的控制效果；结果表明，叶片端区开槽具有工况“自适应”性，可显著抑制角区分离、拓宽可用攻角范围。.相关研究成果，可直接服务于高性能压气机气动设计，为提高我国先进航空发动机的性能提供关键技术支撑!