纳秒脉冲等离子体激励控制激波/边界层干扰的机理研究

Effective control of shock/boundary layer interaction is of great significance for improving the aerodynamic/thermal characteristics and propulsion efficiency for high-speed aircrafts. Nanosecond pulsed plasma excitation is characterized by high efficiency, simple structure and rapid response, which is expected to improve the performance of active flow control methods for high-speed flows. At present, the experimental and numerical research of the plasma exciter in controlling high-speed flow is mostly limited to the phenomenon level, and the deep control mechanism is less involved due to the accuracy and systemic deficiency. Using the deep learning method, the project intends to establish a high-accuracy nanosecond pulsed plasma excitation model through theoretical analysis and experimental observations. Then, coupling the excitation model, we study the flow structure characteristics under different nanosecond plasma excitation parameters and inflow conditions with high-accuracy large eddy simulation method. The controlling mechanism of the plasma actuator for the shock boundary layer interactions are investigated. And the excitation mode and control parameters are optimized according to the interaction mechanism between nanosecond pulsed plasma and shock boundary layer interaction. Effective control method based on the nanosecond pulsed plasma are designed and analyzed for shock-wave boundary layer interactions in a broad Mach number. The research results of the project will provide reference for the flow control of the nanosecond plasma actuator applied to the shock boundary layer interaction, and provide theoretical support and technical reserves for the overall design of the high-speed aircraft and its power system.

有效控制激波/边界层的干扰，对于改善高速飞行器的气动力/热特性及推进效率具有十分重要的意义；纳秒脉冲等离子体激励具有高效率、结构简单且响应迅速等特点，有望提高高速流动主动控制效果。目前该激励器在控制高速流动的实验和数值研究多局限于现象层面，由于精确度及系统性不足等原因较少涉及深层次的控制机理。本项目拟通过理论分析和实验观测结果，利用深度学习方法，建立高精度纳秒脉冲等离子体激励时空作用模型；然后采用耦合激励模型的大涡模拟方法，研究不同激励参数及来流条件下的流动结构特征，探究纳秒脉冲等离子体激励控制激波边界层干扰的作用机理，进而根据纳秒脉冲等离子体与激波边界层干扰的相互作用机制，优化激励器分布方式及控制参数，寻求宽速域激波边界层干扰的有效控制方法。项目的研究成果将为纳秒等离子体激励器应用于激波边界层干扰的流动控制提供参考，为高速飞行器及其动力系统的整体设计提供理论支撑和技术储备。

激波/边界层干扰现象是高速飞行器及其动力装置设计面临的重要问题，已成为限制高速飞行器气动力、热及进气道启动等性能提高的瓶颈之一。纳秒脉冲等离子体激励流动控制技术是一种新型主动流动控制技术，在航空航天领域有广泛的应用前景。本项目采用高精度数值仿真及理论分析，开展了纳秒脉冲等离子体激励器工作特性及激波边界层干扰的控制特性及机理研究。.本项目完成高精度可压缩流大涡模拟方法的构建及纳秒脉冲等离子体激励特性及建模研究，有效提升了纳秒脉冲等离子体激励控制激波／边界层作用非定常流动数值模拟的准确性，为激励器参数影响机理的研究提供科学指导。进一步地基于高精度非定常数值仿真，完成了在纳秒脉冲等离子体激励器作用下，干扰区流动拓扑结构变化及分离区/激波波系及旋涡等结构在时间、空间上的动力学演化规律研究，并分析了激励器主控参数如激励器尺寸、热效应对平均及瞬态流场的作用规律。最后针对激励器效能比及控制效果进行评估，获得了优化的激励器排列方式。本项目为发展未来宽速域飞行器主动流动控制技术提供了新思路，具有应用于宽速域飞行器设计实践的潜力，具有一定的工程应用价值。