The characteristics of surface arc plasma and its control effect on supersonic flow

The characteristic of surface arc plasma included millisecond and microsecond actuation in supersonic flow is investigated both experimentally and numerically. In the experiment, the discharge characteristic of surface arc plasma in quiescent air and supersonic flow is recorded. The stable oblique shock could be observed with millisecond actuation. And the unstable compressive wave could be also observed with microsecond actuation. In the numerical investigation, plasma actuation is defined as a source term with input power density from discharge V–I characteristic, which is expected to better describe the influence of heating process. The numerical results are coincident with experimental results. In order to confirm the capability of surface arc plasma actuation to control supersonic flow, experimental investigations on control shock induced by ramp and separation of boundary layer induced by impinging shock are performed. All the results demonstrate the control effect of surface arc plasma actuation onto supersonic flow.     

EAST装置放电预测的初步研究

用托卡马克模拟程序对实验前期的放电进行了模拟,获得了期望的等离子体演化过程及主要参数波形,如极向场线圈电流、等离子体电流、等离子体位置等。通过等离子体控制系统将模拟获取的参数波形用于实验,开展了等离子体R位置控制、完全程序场控制及RZIp控制下的放电模拟对实验的预测研究。模拟结果与实验吻合较好,表明放电模拟具有一定的可预测性,为今后EAST装置开展更深入的物理实验提供了一定的参考。     

高功率脉冲非平衡磁控溅射放电特性和参数研究

用线圈电流控制非平衡磁场,用汤森放电击穿形成深度自触发放电,用磁阱捕获放电形成的二次电子和导致漂移电流,形成了高功率非平衡磁控溅射放电。采用偏压为-100V相对磁控靶放置的圆形平面电极收集饱和离子电流;在距离磁控靶14cm的位置由Langmuir探针测量浮置电位;示波器测量磁控靶的脉冲电压、电流、浮置电位和饱和离子电流信号。装置的放电脉冲功率达到0.9MW,脉冲频率最大值为40Hz左右,空间电荷限制条件是控制电子电流和离子电流的主要机制。     

气体激光器射频至微波放电激发的某些规律

本文研究了射频至微波激发的Xe和He-Ne原子激光器及CO₂分子激光器,结合各具体激光器的实验结果对其放电物理进行了讨论,提出获得高效率的关键是有效控制放电空间的电子能量,得出了一些有指导意义的结论.     

直流等离子体炬放电特性研究

对于磁约束直流等离子体炬,用氩－氢等离子体的放电体系,研究了等离子体炬几何结构、真空室气压、弧电流、外磁场与比变化等对等离子体炬放电特性的影响。得到了影响等离子体炬宏观和微观参数变化的一些基本规律。     

预试环实验

本文叙述加热场与垂直场分开供电后预试环所作的氢气击穿、平衡、杂散场测量、垂直场波形调整和放电清洗等实验。得到了重复性较好的托卡马克等离子体,其电流峰值为10kA,持续时间2.5ms。     

Point and Multipoint to Plane Barrier Discharge Process for Removal of NOx from Engine Exhaust Gases: Understanding of the Reactional Mechanism by Isotopic Labeling

An experimental study on the removal of NO_x in a simulated vehicle exhaust gas has been carried out using point to plane and multipoint to plane DBD corona reactors. Hydrocarbon (C₃H₆) and NO_x by-products were systematically investigated with a Gas Chromatography coupled to a Mass Spectrometry (GC/MS). NO_x (NO and NO₂) and CO output were also monitored with a gas analyzer in order to complete the mass balance. ¹⁸O tracer technique analyzes is applied to investigate the mechanism of propylene decomposition. From the plasma chemical reaction pathway proposed, it is apparent that the oxygen activation is one of the important steps for initiating the oxidation processes and the R-NO_x formation. We present data for the reaction of the (N₂/O₂/C₃H₆/CO₂NO/H₂O system in the corona discharge reactors mentioned above. This system has been shown to generate a significant amount of aldehyde. CH₃NO₂ and CH₃ONO₂ are the main R-NO_x compounds produced. Reactant composition and discharge energy densities (controlled by a numerical oscilloscope) were the operating parameters under study in wet and dry air mixture. Water vapors played an important role in NO_x removal (especially in NO₂ removal) via the reaction forming HNO₃. Therefore, in wet-gas mixture supplied reactors the highest removal rates of NO_x were as high as 30%, while in dry-gas only 15%. Different dielectric materials such as Al₂O₃/SiO₂ and TiO₂ on Al₂O₃/SiO₂ support have been used.     

Heating,Ionization and Optogalvanic Signals in Argon Hollow Cathode Discharge

The electron gas heating at resonant light irradiation of hollow cathode discharge is measured. The possible channels of opttogalvanic transformation of the absorbed photons are compared and disscised.     

An investigation into the effect of electric field on the performance of Dielectric Barrier Discharge plasma actuators

The influence of the inter-electrode electric field of a single Dielectric Barrier Discharge (DBD) actuator on the performance of the device was investigated. The electric field of the actuator was manipulated through the variation of the angle between the electrodes of the actuators. Response forces generated by the plasma actuators were used as performance indicators for these devices. These forces were measured directly utilizing a highly sensitive balance scale. It was verified that depending on the orientation of the variation of the angle between the electrodes, the performance of the actuator may be decreased or increased when compared to a DBD on a flat dielectric plate more commonly investigated in literature. The manner in which the ionic wind flows over the actuators was also explored in the effort to elucidate the influence of the variation of the angle between the electrodes on the response force generated by the device. Results demonstrated that the response forces generated by the actuators may be improved by up to 50% compared to the actuator configuration on a flat dielectric plate commonly investigated. These results indicate the potential available to advance plasma technology by physically manipulating these devices to increase the performances of the actuators.