水间隙击穿放电模式对激波强度的影响分析
发布时间：2018-07-22 13:04
【摘要】：液体中脉冲大电流放电产生强有力的激波被广泛应用于工业生产、生物医疗等领域,如何稳定、高效地获得高强度的激波是该技术的关键。基于搭建的液电脉冲激波实验平台,该文研究了正极性针 板放电模式对激波强度的影响。通过高速摄像机拍摄流注通道发展过程,发现流注可能呈现出两种不同的发展模式:树枝状亚音速流注与丝带状超音速流注。试验结果表明放电电压对水中间隙击穿放电模式及对应的激波强度有明显影响。通过改变放电电压,可以实现对水中间隙击穿放电模式的调控。亚音速流柱的发展过程属于电热击穿过程,阳极尖端首先出现可见的气泡簇,在外部不均匀电场的作用下气泡簇内部明亮流注沿着尖端向阴极发展,形成树枝状的流注通道。此后,气泡簇包裹的丛林状流注通道不断向阴极发展,当流注头部发展到与阴极距离足够小时,水中间隙击穿并产生强烈的激波。超音速流注的出现可导致间隙的快速动态击穿,电容器上的能量可实现快速释放,形成更为强烈的激波。针对本试验条件,充电电压提升到22.5kV时,亚音速流注将向超音速流注转化,预击穿过程的击穿时延及泄漏能量将迅速降低。研究表明超音速流柱模式的能量转换效率更高,即使在相同的施加电压下,超音速流柱对应激波强度可以达到亚音速流柱模式下的2~4倍。
[Abstract]:The powerful shock produced by pulsed high current discharge in liquid is widely used in industrial production, biomedicine and other fields. How to obtain high intensity shock wave stably and efficiently is the key of this technology. Based on the experimental platform of electro-hydraulic pulse shock, the effect of the discharge mode of the positive needle plate on the shock intensity is studied in this paper. By using high-speed camera to capture the development process of streamer channel, it is found that the streamer may present two different development modes: dendritic subsonic stream and filamentous supersonic stream. The experimental results show that the discharge voltage has a significant effect on the gap breakdown discharge mode and the corresponding shock intensity in water. By changing the discharge voltage, the gap breakdown discharge mode in water can be controlled. The development process of subsonic flow column belongs to electrothermal breakdown process. The visible bubble cluster appears first at the anode tip. Under the action of the external inhomogeneous electric field, the bright flow inside the bubble cluster develops to the cathode along the tip, forming a dendritic flow channel. Since then the Jungle flow channel wrapped in the bubble cluster develops to the cathode. When the flow head reaches enough distance from the cathode the gap in the water breaks down and produces a strong shock wave. The appearance of supersonic flow can lead to the fast dynamic breakdown of the gap, and the energy on the capacitor can be released rapidly, resulting in a stronger shock wave. According to the experimental conditions, when the charging voltage is raised to 22.5 kV, the subsonic flow will be converted to supersonic flow, and the breakdown delay and leakage energy of the pre-breakdown process will be reduced rapidly. The results show that the supersonic flow mode has a higher energy conversion efficiency, and even at the same applied voltage, the corresponding shock intensity of the supersonic flow column can reach 2 ~ 4 times that of the subsonic flow mode.
【作者单位】： 强电磁工程与新技术国家重点实验室(华中科技大学);
【分类号】：O461.25
本文编号：2137554
[Abstract]:The powerful shock produced by pulsed high current discharge in liquid is widely used in industrial production, biomedicine and other fields. How to obtain high intensity shock wave stably and efficiently is the key of this technology. Based on the experimental platform of electro-hydraulic pulse shock, the effect of the discharge mode of the positive needle plate on the shock intensity is studied in this paper. By using high-speed camera to capture the development process of streamer channel, it is found that the streamer may present two different development modes: dendritic subsonic stream and filamentous supersonic stream. The experimental results show that the discharge voltage has a significant effect on the gap breakdown discharge mode and the corresponding shock intensity in water. By changing the discharge voltage, the gap breakdown discharge mode in water can be controlled. The development process of subsonic flow column belongs to electrothermal breakdown process. The visible bubble cluster appears first at the anode tip. Under the action of the external inhomogeneous electric field, the bright flow inside the bubble cluster develops to the cathode along the tip, forming a dendritic flow channel. Since then the Jungle flow channel wrapped in the bubble cluster develops to the cathode. When the flow head reaches enough distance from the cathode the gap in the water breaks down and produces a strong shock wave. The appearance of supersonic flow can lead to the fast dynamic breakdown of the gap, and the energy on the capacitor can be released rapidly, resulting in a stronger shock wave. According to the experimental conditions, when the charging voltage is raised to 22.5 kV, the subsonic flow will be converted to supersonic flow, and the breakdown delay and leakage energy of the pre-breakdown process will be reduced rapidly. The results show that the supersonic flow mode has a higher energy conversion efficiency, and even at the same applied voltage, the corresponding shock intensity of the supersonic flow column can reach 2 ~ 4 times that of the subsonic flow mode.
【作者单位】： 强电磁工程与新技术国家重点实验室(华中科技大学);
【分类号】：O461.25
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，本文编号：2137554
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