针板结构极不均匀电场中气泡迁移特性与吸附静止状态的绝缘特性分析

Analysis of Migration Characteristics and Insulation Characteristics with Adsorption Static State of Bubbles in Extremely Inhomogeneous Electric Fields of Needle Plate Structures

以去离子水作为冷却介质的换流阀散热系统难以同时兼顾绝缘与散热性能,影响了系统的可靠运行。相变冷却技术凭借卓越的散热能力正在逐步应用于高压大功率电力电子器件的冷却,但液体电介质中的气泡有绝缘劣化的风险。为更好掌握相变冷却气泡在极不均匀电场中的迁移特性和绝缘特性,采用数值模拟的方法分析了气泡粒径、速度和电场强度这3个关键因素对气泡运动轨迹的影响;研究了进入低场区后不同接触角气泡,对绝缘子表面电场强度的影响。研究结果揭示了各因素对气泡运动轨迹的显著影响,加深了对相变冷却气泡迁移特性和绝缘特性的认知,对直流装备相变冷却的进一步应用具有重要参考价值。

Using deionized water as the cooling medium,the cooling system of phase-change valve faces challenges in balancing insulation and heat dissipation performance,which affects the reliable operation of the system.Leveraging superior heat dissipation capabilities,phase-change cooling techniques are being gradually applied for cooling high-voltage high-power power electronic devices.However,bubbles in the liquid dielectric pose risks of insulation degradation.To better understand the migration characteristics and insulation characteristics of bubbles in the extremely inhomogeneous electric field associated with phase-change cooling,numerical simulation methods are applied to analyze the effects of three key factors on the trajectory of bubble motion,which are bubble diameter,velocity and electric field strength.Furthermore,after entering low field strength regions,the impact of bubbles with different contact angles,on the electric field distribution over insulator surfaces has been studied.The results reveal significant ef⁃fects of various factors on bubble motion trajectories,provide an improved understanding of bubble migration and insulation characteristics in phase-change,and hold important reference value for the further application of phase-change cooling in DC equipment.