跨音速轴流压气机内部激波-边界层干涉机理及控制研究

Transonic Axial Flow Compressors (AFC) are crucial components of jet engines and heavy-duty gas turbines. The internal flow of transonic AFC is under highly adverse pressure gradient and extremely complex, where the shock wave and end-wall boundary layer separation are typically present and their interactions are also intense, which influence largely the AFC aerodynamic performance and stability. .The previous investigators did significant work to suppress the blade passage shock and end-wall boundary flow separation by separately varying the sectional blade profile or varying stacking line. But simultaneous variation of both has yet been attempted, which has constrained the effectiveness of flow control. Simultaneous variation of both sectional blade profile and stacking line can increase considerably the dimension and nonlinearity of the problem, and it would become very complex and difficult to be resolved. Quite recently, the team of the applicant has successfully developed the efficient parallel and global optimization method of adaptive surrogate model, with which the simultaneous variation of both sectional profile and its stacking line are realized. The blade passage shock wave and flow separation are mitigated and subsequently the overall performance and stability are significantly enhanced. Such work is acknowledged by the international peers and we have been awarded the “Donald Julius Groen Prize 2014” by the IMechE. However, in our previous work, we varied simultaneously the sectional profiles and their stacking lines to mitigate the blade passage shock but did not consider the end-wall boundary layer separation. Besides, the interaction of between end-wall flow separation and shock wave, and its sensitivity to the variation of the sectional profiles and their stacking lines are also not clear, and require and in-depth study. On the basis of our previous work, in the present project, we will focus on the interaction of end-wall flow separation and shock wave and try to understand its mechanism. We will also investigate the influence of the blade 3D variation (in terms of sectional profiles and their stacking line) on interaction of end-wall flow separation and shock wave and establish the relation between the geometric variation and interaction of end-wall flow separation and shock wave. Then we will develop the effective methodology to mitigate simultaneously the shock and end-wall flow separation by means of blade geometry variation. Based on the above mentioned achievement, the existing in-house 3D blade design method and code of transonic AFC will be improved, where the shock wave and end-wall flow separation will be effectively mitigated through simultaneous variation the sectional profiles and their stacking line. Moreover, the experimental study will be conducted on the flow and overall performance for the redesigned AFC stage, by which the numerical approaches will be verified. The results arising from this project will be beneficial for the national undertakings of jet engines and heavy-duty gas turbines.

跨音速轴流压气机是航空发动机和重型燃气轮机的核心部件，其内部以强逆压梯度下的激波及端壁边界层分离为主要特征，且二者干涉严重，显著影响压气机气动性能及气动稳定性。前人分别使用叶片基元叶型形变或积叠线形变抑制激波和边界层分离。但二者同时变形因问题复杂性和难度骤增未能实现，限制了流动控制效果。最近本课题组借助自适应全局并行算法，实现了基元叶型及积叠线最优协同变形，抑制了叶道激波和分离流，显著提升了压气机气动性能及稳定性，得到了国际同行认可。但目前工作尚未考虑叶片形变对端壁边界层分离的抑制。本项目将在前期工作基础上，探明激波-边界层干涉机理，明晰全三维形变对激波-边界层干涉的影响，建立二者的相关关系。获得利用叶片全三维形变有效抑制激波和边界层分离的方法，实现激波和边界层分离的最优控制。开展模型级流场和性能实验研究，验证并完善数值方法。为国家蓬勃发展的航空发动机和重型燃气轮机事业提供支撑。

跨音速轴流压气机是航空发动机和重型燃气轮机的核心部件，其内部以强逆压梯度下的激波及端壁边界层分离为主要特征，且二者干涉严重，显著影响压气机气动性能及气动稳定性。前人分别使用叶片基元叶型形变或积叠线形变抑制激波和边界层分离。但二者同时变形因问题复杂性和难度骤增未能实现，限制了流动控制效果。.本项目以研究跨音速轴流压气机复杂内流机理和特性为出发点，发展利用最优三维形变控制激波和边界层分离流的有效方法，提升跨音速轴流压气机的气动性能和气动稳定性。通过数值研究探明了激波-边界层干涉机理，明晰了三维叶片协同形变作用机制，建立了三维叶片几何形变和激波-边界层干涉、压气机气动性能及气动稳定性之间的相关关系；在前期工作基础上发展了跨音速压气机三维叶片多目标优化平台，利用叶片全三维形变有效抑制激波和边界层分离，实现激波和边界层分离的最优控制，有效提升了压气机的效率及压比；在流动机理研究的基础上，提取了流动失稳特征参数，并将自适应优化方法与流动失稳特征化参数相结合，建立了以压气机增效扩稳为目标的优化方法，显著改善了压气机的气动性能和稳定工况范围；建立了基于偏好驱动的叶片优化方法，显著提升了多目标优化的效率，该优化方法有助于解决复杂多目标气动设计问题，为有效挖掘跨音压气机多目标优化潜力提供支撑；通过建立损失与翼型几何的相关性，发展了一种新型的损失系数计算方法，并提出了一种基于全局优化的跨音速轴流压气机通流设计方法，可对具有大量设计变量及多重设计目标的复杂设计问题进行高效求解，满足多级压气机高效率宽裕度的设计要求。.以上研究成果将为国家大力发展的航空发动机及重型燃气轮机事业提供支撑，具有重大社会意义和实际应用价值。此外，本项目发展的自适应协同优化方法，可为各类叶轮机械内流控制及设计优化提供支撑，具有较高的实用性和广泛应用潜力。