等离子体激励调控亚声速压气机叶型附面层流动探索研究

附面层对压气机叶型气动性能有关键影响，发展调控叶表附面层流动的主动控制技术具有重要意义。等离子体激励具有频带宽、结构简单和不改变控制型面等特点，应用于附面层流动的调控具有较好的可实现性。申请人提出等离子体激励调控亚声速压气机叶型附面层流动抑制流动分离的创新构思。首先通过构造来流条件可变的扩压通道模拟压气机内流环境，研究揭示强来流扰动与逆压梯度下等离子体激励特性，为设计可有效调控压气机叶型附面层流动的等离子体激励参数提供依据。然后选取一典型CDA叶型，将等离子体激励以不同布局施加于叶片表面，通过调控附面层流动诱导形成压缩波、展向/流向涡，利用大涡模拟与叶栅实验，研究不同来流扰动、马赫数、攻角以及激励参数下诱导流动与分离流动的相互作用以及对附面层发展的影响，揭示等离子体激励通过增强分离区与主流区掺混以及促进附面层转捩，抑制叶型可用攻角范围外大尺度以及可用攻角范围内小尺度流动分离的规律和机制。

Boundary layer is very crucial to the aerodynamic performance of compressor airfoil, so it is of great significance to develop active control technique to control the compressor airfoil boundary layer flow. Plasma actuation is characterized by wide actuating frequency, simple structure and will impose no influences on the geometric profiles to be controlled. With these characteristics, plasma actuation is considered to be of good realizability in controlling the boundary layer flow. The applicant puts forward the innovative research idea of controlling the subsonic compressor airfoil boundary layer flow to suppress flow separations. At first, a divergent passage flow will be used to simulate the compressor internal flow and the inlet flow conditions can be changed during the research. The characteristics of plasma actuations under strong inlet flow disturbances and adverse pressure gradient will be studied systematically, and the results will act as the basis for designing the plasma actuation parameters which can control the compressor blade airfoil boundary layer flow effectively. Then, plasma actuations with different layouts will be imposed on the blade surface of a typical CDA airfoil to induce compressive wave, spanwise and streamwise vortexes through controlling the boundary layer flow. The interactions between the induced flow and the separated flow as well as the influences of the induced flow on the boundary layer flow development under different inlet flow disturbances, Mach number, incidences and actuation parameters will be studied using LES simulations and cascade experiments. The airfoil flow separations within and without the usable incidence range are supposed to be suppressed by the plasma actuation, through enhancing flow mixing between separation zone and main flow zone or promoting boundary layer transition, and the corresponding control law and mechanism will be uncovered.