Pressure Rise due to an Underwater Arc in a Closed Vessel Containing Air and Water

Pressure Rises Due to Arc Under Insulating Oil in Closed Vessel—Relationship between Bubble Behavior and Pressure Rises

“…Based on the test results for the arc in water in air–water two‐phase system closed vessel , we focused on the frequency component of the pressure waveform, applied signal processing with 500 Hz threshold value to separate the pressure waveform into low‐frequency side and high‐frequency side, and discussed pressure rise phenomenon. Specifically, it has been stated that the low‐frequency side appears as bubble expansion/contraction derived gas/liquid phase pressure variation, and the high‐frequency side appear as bubble formation/collapse derived liquid phase pressure pulse.…”

“…However, the reports so far mainly study the correlation of arc energy with constant pressure rise and the transitional pressure rise inherent to the real machine equipped with pressure release mechanism, and the fundamental property of arc and the associated pressure rise phenomenon as well as the influences of arc generation position and equipment structure on pressure rise phenomenon have not been clarified. Thus, as the first step to clarify the characteristics of pressure rise/propagation resulted by arc in insulating oil as well as its mechanism, we have worked on both experimental test and analysis of arc in water of the air–water two‐phase system in a closed vessel. The results revealed that the pressure rise of gas phase is caused through the change in gas–water interface determined by the volume of bubbles formed by arc.…”

Pressure Rises Due to Arc under Insulating Oil in Closed Vessel—Pressure Fluctuation of Depth Direction in Oil

“…In this context, we in our institute aim at clarifying propagation characteristics and mechanisms of pressure rise due to arcs in insulating oil; as a previous step, we carried out experiments and analysis of underwater arc in a closed vessel with air-water two-phase system. As a result, in the experimental aspect, we found out among the other things that pressure of the air phase changes accordingly to the bubble volume in water, and that sharp pressure pulses are generated during bubble formation and destruction [4,5]. As regards analysis, we developed a method for pressure rise analysis based on fundamental equations of mass conservation law, momentum conservation law, and energy conservation law; we also verified the method through comparison with experimental results [6].…”

“…As a result, in the experimental aspect, we found out among the other things that pressure of the air phase changes accordingly to the bubble volume in water, and that sharp pressure pulses are generated during bubble formation and destruction [4,5]. As a result, in the experimental aspect, we found out among the other things that pressure of the air phase changes accordingly to the bubble volume in water, and that sharp pressure pulses are generated during bubble formation and destruction [4,5].…”