电磁复合等离子体气动激励控制激波的机理研究

The method of plasma flow control is a noval active flow control technique with several advantages such as strong actuation intensity, wide actuation band, free of moving parts and so on, which could significantly improve the characteristics of aircraft and aero-engine. At present, the basic mechanism of shockwave control with arc discharge has been preliminarily revealed internationally, but there are still some problems to study, such as low actuation intensity, the changing rules of actuation characteristic and its coupling of supersonic boundary layer. In this project, based on the experiment, the mechanism investigation of shockwave controlling with electromagnetic combined plasma actuation will be conducted, through time resolved emission spectrum diagnosis, high spped schlieren and nano-based planar laser scattering and particle image velocimetry tests for flow field, the changing rules of some key parameters such as rotational and vibrational temperature of molecule, electronic temperature, electron density, the temperature and pressure and density of the fluid during the electromagnetic combined plasma actuation will be acquired, also the correlation mechanism between electromagnetic combined plasma actuation and supersonic boundary layer will be revealed. With the multi-physics numerical simulation and wind tunnel experiments, the influencing rules of actuation parameters on control effect and the physic mechanism of enhancing the actuation intensity and control ability would be studied. The work mentioned above will technically support the research on drag reduction during supersonic cruise, shockwave control during hypersonic flight and so on.

等离子体流动控制是一种新型的主动流动控制技术，具有响应迅速、作用频带宽和控制灵活等技术优势，可以显著提升飞行器、动力装置气动性能。目前，国际上已初步揭示了电弧放电等离子体气动激励控制激波的基本原理，但是还存在激励强度弱，对激励特性的变化规律及其与超声速附面层耦合作用的机制尚不清楚等问题。本项目在初步实验的基础上，进行电磁复合等离子体气动激励控制激波的机理研究，通过等离子体特性的发射光谱诊断，流场的高速纹影、NPLS和PIV等测试，得到电磁复合等离子体气动激励的转动与振动温度、电子温度与密度，温度场、压力场和密度场等关键参数随时间的变化规律，揭示电磁复合等离子体气动激励与超声速附面层耦合作用机制；结合多场耦合数值仿真和风洞实验，获得各激励参数对控制激波效果的影响规律，揭示提高激励强度和控制激波能力的物理机制。为未来的飞机超声速巡航减阻、高超声速飞行器激波控制等应用领域提供新的技术途径。

等离子体流动控制是一种新型的主动流动控制技术，具有响应迅速、作用频带宽和控制灵活等技术优势，可以显著提升飞行器、动力装置气动性能。本项目在初步实验的基础上，重点进行了电磁复合等离子体气动激励特性的测试诊断、电磁复合等离子体气动激励控制激波风洞实验和数值仿真三方面的研究。通过本项目的研究，研制了钨电极和陶瓷绝缘介质的电弧放电激励器，可以较好地承受电弧放电的高温烧蚀和高电压击穿，在相同的输入电压条件下，能够提供更大的放电电流。得到了电源在静止空气条件以及超声速气流中的放电特性，获得了电弧诱导产生的冲击波的特性和规律。完成了等离子体气动激励减弱长方体脱体激波强度、等离子体气动激励减弱钝头体脱体激波强度、等离子体气动激励控制翼型激波阻力的实验研究，得到了不同激励条件下的影响规律。实现了电磁复合等离子体气动激励有效减弱翼型正激波强度27.5%，减弱尖劈斜激波强度43.61%，减弱长方体脱体激波强度23.3%，减弱钝头体脱体激波强度5.5%。建立了基于实验数据的唯象仿真模型和多场耦合的等离子体-流场耦合仿真模型，进行了减小超声速翼型激波阻力仿真研究，考虑磁场效应的减小超声速翼型激波阻力数值研究，研究得到了激励参数对控制效果的影响规律。提出了电磁复合等离子体气动激励控制激波的作用机理，其通过表面电弧激励产生局部高温的等离子体区域依附于物体表面，在超声速流场中形成了局部壅塞现象，改变了物体自身外形，形成了新的虚拟型面，改变原有激波结构和强度，即为焦耳热效应。放电功率和有无磁场作用对控制效果起到决定性作用，增大放电功率和磁场强度，可显著提高电磁复合等离子体气动激励的强度和在超音速来流下放电的稳定性，从而提高其控制激波的能力。研究成果可为未来的飞机超声速巡航减阻、高超声速飞行器激波控制等应用领域提供新的技术途径。