Due to the limited production technology and various external factors, there are impurities and suspended air bubbles in transformer oil, which can quickly form "small bridges" in the high field strength area and lead to transformer breakdown. This paper establishes a simulation model of gas-liquid two-phase flow under the coupling of electric-fluid-thermal multi-physical fields based on the level set method. The motion characteristics of bubbles are investigated under different flow rates, oil channels, and numbers of bubbles. The effects of single-bubble deformation and multi-bubble fusion on electric field distortion are analyzed with the bubbles’ maximum field strength change curve. The results of the study show that the maximum internal field strength decreases when the bubbles in the horizontal and vertical oil channels are deformed in the direction of the electric field and increases when they are deformed in the direction perpendicular to the electric field, the greater the velocity of the oil flow the more severe the bubble deformation and the more serious the field distortion. In the case of dual oil channels, the maximum field strength inside the bubble depends mainly on the deformation of the bubble in the horizontal oil channel, and the fusion of multiple bubbles results in severe field distortion at the bubble intersection.

Xiao Lei. Characterizations of air bubble movement in different transformer oil channel structures. International Journal of Frontiers in Engineering Technology (2023), Vol. 5, Issue 7: 42-49. https://doi.org/10.25236/IJFET.2023.050707.

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