【作者】 夏胜国；

【导师】 潘垣； 刘克富；

【作者基本信息】 华中科技大学 ， 电气工程， 2004， 博士

【摘要】 脉冲消融毛细管等离子体发生器产生的等离子体射流具有高密度和相对低温的特性,在电热发射和电热化学发射以及其他科学研究和工业应用领域都具有潜在的应用前景。本文提出一种新型的两间隙毛细管结构,解决了毛细管的重复放电问题。这种结构的毛细管本身具有电流开关的作用,因而不再需要大电流脉冲开关装置,简化了脉冲功率电源系统。文中通过两间隙毛细管在 1 千焦电能水平下的主间隙放电实验,仔细研究了消融控制电弧负载的稳定阻抗、峰值电流、电弧电压和放电功率等主要放电特征参量随毛细管几何尺寸、放电电容以及起始充电电压等放电参数的变化规律,考察了两间隙毛细管的使用寿命和在重复放电时的放电特性。利用主放电的数值模拟研究了各放电参数对两间隙毛细管的质量密度、压强、温度和速度等出口参数的影响,给出了生成的等离子体的各种基本性质。文中建立了一个两间隙毛细管的触发放电模型,模型考察了管壁消融对触发放电过程的影响,发现管壁消融能大幅度地减小触发时延。模型同时给出了计算触发时延的方法。文中提出了一种含耦合电感的双脉冲电源电路,并从理论和实验两方面验证了双脉冲电路应用于电热化学发射技术的可行性。总之,本文围绕两间隙毛细管的工作特性进行了系统的实验和理论研究,所得到的结果不但为消融毛细管等离子体的工程实践提供了丰富的信息,也为消融放电等离子体科学与技术领域进一步的研究工作提供了若干新的观点和方法。更多还原

【Abstract】 Electrothermal plasmas are characterized by high number densities andrelatively low plasma temperatures. Electrothermal plasma devices are of greatimportance in electrothermal or electrothermal chemical launchers and many othertechnological applications. In this thesis , a novel two-gap capillary plasma generator (TGCPG) isdeveloped as a realistic alternative to the conventional capillary in electrothermallaunchers and expected to be a versatile capillary plasma generator for otherapplications. It is designed to accomplish two goals: repetitive operation and acompact power supply system in which capillary itself serves as a closing switch. Inaddition, a simple power conditioning system with which a two-pulse dischargecurrent curve can be generated for electrothermal launchers is also developed and itsfeasibility is theoretically and experimentally examined. In the experimental part of this thesis, the dependence of characteristics of themain discharge on the size of capillary, main capacitor and its initial charged voltageis obtained. The life expectation of TGCPG and the stability of the dischargecharacteristics under repetitive operation are examined. The dependence of thetrigger delay time of TGCPG on the capillary size and trigger energy is also studied. Two one-dimensional time-dependent models of TGCPG are proposed tosimulate the trigger process and the main discharge process respectively. Thedependence of the exit parameters such as plasma density, pressure, temperature andvelocity on the size of capillary, main capacitor and its initial charged voltage isstudied, the trigger delay time is also calculated and its comparison with theexperimental results gives a good agreement. It is found that capillary wall ablationcan greatly change the behavior of trigger discharge arc and drastically diminishesthe trigger delay time. In a word, this study focus on the characteristics of plasmas generated inTGCPG discharges by ablation-stabilized arcs, and some valuable conclusions aredrawn.更多还原