Dynamic evolution of liquid phase disturbance and its critical influence on pre-breakdown process

• Published in: Physics of fluids (1994) 2022-06, Vol.34 (6)
• Main Authors: Li, Xian-Dong, He, Hua, Xiao, Tian-Fei, Lan, Ming-Yan, Xiong, Ding, Li, Jian
• Format: Article
• Language: English
• Subjects: Breakdown; Electric potential; Evolution; Fluid dynamics; Liquid phases; Physics; Prebreakdown; Shrinkage; Voltage
• ISSN: 1070-6631; 1089-7666
• DOI: 10.1063/5.0087556

Liquid phase disturbances are often observed in pre-breakdown processes; however, their dynamic behaviors are rarely studied. In this paper, time evolution characteristics of liquid phase disturbance under ultra-long pulses (>100 ms) were investigated. The results showed that the steady expansion of liquid phase disturbance follows the pattern of constant heating power, volume growth rate, and liquid temperature (about 52 °C unvaried with applied voltage). The shrinkage of liquid phase disturbance with the applied voltage leads to the breakdown transition from a full disturbed phase mode to a partial disturbed phase mode. Further research indicated that the liquid phase disturbance has a significant influence on the development of subsonic streamers (especially for positive polarity). In the disturbed phase of liquid, the streamers propagate faster with a plump morphology than in the stationary phase. The local turbulences at the boundary of the disturbed phase can retard the streamer propagation remarkably and lead to the streamer branching. Finally, the abnormal downtrend of positive streamers' average velocity varied with the applied voltage due to the shrinkage of liquid phase disturbance was predicted and observed for the first time.