电场和温度协同作用对纳米SiO2改性绝缘油中水分子扩散行为的影响

Effects of Electric Field and Temperature Synergism on Diffusion Behavior of Water Molecules in Nano-SiO Modified Insulating Oil

利用分子模拟技术研究了电场和温度对纳米SiO2改性绝缘油中水分子扩散行为的影响。结果表明:电场会使水分子发生极化,使得水分子由原本的无序排列变为沿着电场方向的有序排列。因此,电场的加入减弱了水分子的布朗运动,降低了水分子在油中的扩散能力;而且电场的加入增强了水分子与油介质之间的静电作用力,其数值是无电场作用下的2~3倍,这也是电场作用下两者间相互作用能增大的主要原因。此外,在电场的作用下,模型的自由体积分数减小,温度对模型中O原子和H原子之间氢键的影响减弱。

The effects of electric field and temperature on the diffusion behavior of water molecules in nano-SiO2 modified insulating oil were studied by molecular simulation technology. The results show that the water molecules are polarized under electric field, and the water molecules would change from an original disordered arrangement to an ordered arrangement along the direction of electric field. Therefore, under the action of electric field,the Brownian motion of water molecules weakens, and the diffusion ability of water molecules in oil decreases.The electrostatic force between water molecules and oil medium was enhanced by electric field, which is 2-3 times bigger than that without electric field. This is also the main reason for the increase of interaction energy between water molecules and oil medium under electric field. In addition, under the action of electric field, the free volume fraction of the model decreases, and the effect of temperature on the hydrogen bond between O and H atoms in the model weakens.