高效的流动控制方式对于提升高超声速飞行器气动性能、增强飞行机动性和提高飞行器推进效率至关重要。新兴超导材料及电磁技术的发展使得磁流体流动控制技术有望成为高超声速流动控制技术的新突破口，以解决飞行器在“极端”环境和“极端”动力条件下飞行所面临的降热、减阻、控制、通讯等难题。磁流体控制技术利用外加磁场影响高超声速飞行器强激波后离子和电子的运动规律，它可以有效改善飞行器的气动特性，在飞行器气动力操控和气动热环境管理等方面具有广阔的应用前景。我国《国家中长期科学和技术发展规划纲要(2006-2020 年)》也将磁流体列为“面向国家重大战略需求的基础研究”中的航空航天重大力学问题之一。

  本文发展基于高温真实气体效应的磁流体动力学边界层理论及准一维驻点线方法，结合数值模拟方法系统研究磁场对激波结构、壁面热流以及气动力等参数的影响规律和机理，并首次在爆轰驱动激波风洞中发展高超声速流动和磁场相互作用的试验技术，获得了典型的磁控脱体激波实验数据。论文的主要研究内容概括如下：

  1) 基于电磁学与流体力学基本理论开发磁流体流动控制的全磁雷诺数与低磁雷诺数计算方法，并针对高超声速飞行器的飞行特征，数值研究高温真实气体效应下，磁流体流动控制对激波结构、气动热以及阻力特性的影响规律和机理；其次，对不同飞行高度、磁感应强度、磁场类型以及模型尺寸的磁控影响进行分析，为实现最佳磁控效果提供支撑；另外，对双锥模型中磁流体流动控制下的激波与激波/边界层相互作用规律进行分析。

  2) 发展基于高温真实气体效应的磁流体驻点边界层理论，利用磁流体驻点边界层理论对驻点热流快速评估，并通过理论方法获得不同边界以及磁场条件下的边界层内参数分布规律；其次，结合传统驻点线模型和磁流体流动作用规律，引入电磁力影响下的牛顿理论以及激波曲面修正模型，发展磁流体流动的准一维驻点线理论，实现对磁流体流动控制下的驻点流动规律进行高效、准确的分析，指导相关实验方案设计。

  3) 针对高焓流动磁流体流动控制实验对流场作用环境的高要求，发展适用于爆轰驱动激波风洞的磁流体流动控制实验方法，通过该设计方法实现对爆轰驱动激波管以及喷管的流动状态、参数分布的准确评估。结合磁流体流动控制实验对总温、总压以及实验气体介质特性的要求，设计多组磁流体流动控制实验状态。利用 JF10/JFX/800 等高焓设备开展磁流体流动控制实验，获得不同状态下典型脱体激波距离实验结果，为数值模拟中获得的流动控制规律以及发展的一维驻点线理论模型提供了实验数据支撑。 

  Efficient flow control in hypersonic flights is very important to improve aerodynamic performance, flight maneuverability and propulsion efficiency of hypersonic vehicles. With the development of superconductors and electromagnetic technologies, magnetohydrodynamics (MHD) flow control is expected to be a promising breakthrough to solve the problems of heat reduction, drag reduction, control, communication and others in hypersonic flow control techniques. In MHD flow control, external magnetic field is deployed to influence movements of ions and electrons, which are originated from a weakly plasma flow in the shock layer in front of hypersonic flight vehicles. This can effectively improve the aerodynamic characteristics of hypersonic vehicles and exhibits extensively potential applications in aircraft aerodynamic controls and aerodynamic thermal environment managements. The outline of the national medium- and long-term science and technology development plans (2006-2020) also lists magnetic fluid as one of the major mechanical problems of aerospace in the "basic research facing the major strategic needs of the country".

  Based on the real gas effect at high temperature, the magnetohydrodynamic boundary layer theory and quasi one-dimensional stagnation streamline method are developed in this thesis. The effect of electromagnetic field on shock structure, wall heat flux and drag parameters are comprehensively studied in combination with numerical simulation approaches. Experimental techniques are also established to study the interactions between hypersonic flow and electromagnetic field in detonation-driven shock tunnels for the first time, typical experimental data of detached shock structure controlled by electromagnetic are obtained. The main contents are summarized as follows:

  1) Based on the basic theories of electromagnetism and hydrodynamics, mathematical models for full- and low-magnetic Reynolds number of MHD flow are determined. According to the flight characteristics of hypersonic vehicles, the effect of electromagnetic field on shock structure, aerodynamic heat and aerodynamic resistance characteristics in real gas effect due to the high-temperature effect are systematically analyzed using numerical simulation. Analysis is performed to investigate magnetic effects under various flight altitude, magnetic field intensity, magnetic type and model, and thus provide valuable information in optimizing the magnitic control. Furthermore, the interactions between shock wave and shock/boundary layer under the conditions of MHD flow control of double cone models are studied.

  2) Developing the theory of MHD boundary layer at the stagnation points based on high-tempwrature real gas effects, which can be a guidance to the MHD flow control experiment and its engineering application. Based on the boundary layer theory in high temperature gas effect, the parameter distribution in the boundary layer with different boundary conditions and magnetic field conditions can be analyzed quickly. Based on the traditional stagnation streamline method, the Lorentz force is firstly added to the dimensionally reduced Navier-Stokes equations (DRNSE), and the shock curvature parameter is incorporated to improve the method’s accuracy. The proposed high-efficiency model can be used to investigate the overall quantitative behavior of physical-chemical phenomena in hypersonic MHD flows.

  3) According to the high requirements of high enthalpy MHD flow control experiment on the flow field environment, the design methods suitable for detonation driven shock tunnel are developed. And the freestream conditions of detonation driven shock tunnel are also accurately evaluated by the design methods. Meanwhile, combined with the requirements of MHD flow control experiment on reservoir temperature, reservoir pressure and ionization properties of the experimental gas medium, multiple groups of MHD flow control experimental states are designed. Using JF10/JFX and other high enthalpy equipment to carry out MHD flow control experiments, the experimental results of typical shock standoff distance under different conditions are obtained, which provides experimental data support for the MHD flow control laws obtained in numerical simulation and the developed quasione-dimensional model for the stagnation streamline.