变压器油中气泡运动特性及聚并影响因素分析

Analysis of Bubble Motion Characteristics and Coalescence Influencing Factors in Transformer Oil

为厘清变压器油中气泡在流场与电场耦合效应下复杂的动力学行为,并探究其诱发电场的局部畸变,进而潜在地损害变压器油的绝缘特性。本文通过建立流场与电场的耦合模型,研究了极不均匀电场下,气泡尺寸对于气泡畸变特性以及气泡内电场畸变的影响,分析了气泡的数目、气泡初始位置对油中气泡的聚并行为以及气泡内最大电场强度的影响,并探究了气泡运动过程中油中电场分布以及气泡破裂现象。结果表明:气泡畸变率与气泡内部最大电场强度同气泡尺寸呈正相关,电场增强率平均为1.72倍。气泡聚并时间和气泡内部电场强度均随着气泡数目和气泡初始位置角度的增大而逐渐提前和逐渐增大。研究过程中还发现气泡内部场强的最大值主要位于气泡与周围介质的交界面处,并且聚并后生成的大气泡存在破裂的可能性。

In order to clarify the complex dynamic behavior of bubbles in transformer oil under the coupling effect of flow field and electric field,and to explore the local distortion of electric field induced by bubbles,and then potentially damage the insulation characteristics of transformer oil.In this paper,by establishing a coupling model of flow field and electric field,the influence of bubble size on bubble distortion characteristics and electric field distortion in bubbles under extremely uneven electric field is studied.The effects of the number of bubbles and the initial position of bubbles on the coalescence behavior of bubbles in oil and the maximum electric field intensity in bubbles are analyzed,and the electric field distribution and bubble rupture phenomenon in oil during bubble movement are explored.The results show that the bubble distortion rate and the maximum electric field intensity inside the bubble are positively correlated with the bubble size,and the average electric field enhancement rate is 1.72 times.The bubble Coalescence time and the electric field intensity inside the bubble gradually advance and increase with the increase of the number of bubbles and the initial position angle of the bubble.During the study,it was also found that the maximum value of the internal field strength of the bubble was mainly located at the interface between the bubble and the surrounding medium,and the large bubbles generated after the coalescence had the possibllity of rupture.