绝缘油在水和酸共同作用下的分子动力学模拟
Molecular Dynamics Simulation of Insulating Oil Under the Interaction of Water and Acid

为探讨水分和温度对变压器油中酸扩散行为的影响，在分子模拟软件内建立了水分子、矿物油分子、甲酸分子的复合模型，水的体积分数分别为1%，3%，5%，甲酸的质量分数为3%。通过分子动力学方法模拟计算了甲酸分子在不同含水量油模型中的扩散系数、径向分布函数以及复合模型的总动能；此外，选取了水体积分数为1%的复合模型为研究对象，以温度为变量进行动力学模拟。结果表明：随着水含量的增多，甲酸的扩散系数并没有逐渐增大，甲酸分子与水分子之间的氢键数目呈逐渐减少的趋势。而随着温度的升高，油模型具有的动能越大，酸分子的扩散逐渐增强。油模型中，含水量越多，水和酸在热运动下碰撞油分子的能量越大；温度越高，相互之间的碰撞越激烈。模拟结果说明水分增加或温度增高，均对油分子的结构稳定性造成一定程度的破坏。
To investigate the effects of moisture and temperature on acid diffusion behavior in transformer oils, a complex model of water molecules, mineral oil molecules, and formic acid molecules was established in molecular simulation software. The volume fraction of water was 1%, 3%, and 5%, respectively. The quality score is 3%. The diffusion coefficients and radial distribution functions of formic acid molecules in oil models with different water contents and the total kinetic energy of the composite model were calculated by using molecular dynamics method. In addition, a composite model with a water volume fraction of 1% was selected as the study object, and temperature was used as a variable for dynamic simulation. The results showed that with the increase of water content, the diffusion coefficient of formic acid did not increase gradually, and the number of hydrogen bonds between formic acid molecule and water molecule also showed a tendency to decrease gradually. As the temperature increases, the kinetic energy of the oil model increases and the diffusion of acid molecules gradually increases. In the oil model, the greater the water content, the greater the energy of water and acid collisions with oil molecules under thermal motion; the higher the temperature, the more intense the collision between them. It shows that the increase of water or the increase of temperature all cause a certain degree of damage to the structural stability of oil molecules.