Department of Chemistry, University of Southampton, Highfield, University Road, Southampton SO17 1BJ, U.K.
Schaeffler Technologies AG & Co. KG, Industriestraße 1-3 91074, Herzogenaurach, Germany.
J Phys Chem B. 2023 Mar 23;127(11):2587-2594. doi: 10.1021/acs.jpcb.2c08553. Epub 2023 Mar 8.
Synthetic esters are used as lubricants for applications at high temperatures, but their development can be a trial and error process. In this context, molecular dynamics simulations could be used as a tool to investigate the properties of new lubricants, in particular viscosity. We employ nonequilibrium molecular dynamics (NEMD) simulations to predict bulk Newtonian viscosities of a set of mixtures of two esters, di(2-ethylhexyl) sebacate (DEHS) and di(2-ethylhexyl) adipate (DEHA) at 293 and 343 K as well as equilibrium molecular dynamics (EMD) and NEMD at 393 K and compare these to experimental measurements. The simulations predict mixture densities within 5% of the experimental values, and we are able to retrieve between 99% and 75% of the experimental viscosities for all ranges of temperature. Experimental viscosities show a linear trend which we are able to capture using NEMD at low temperature and EMD at high temperature. Our work shows that, using EMD and NEMD simulations, and the workflows we developed, we can obtain reliable estimates of the viscosities of mixtures of industrially relevant ester-based lubricants at different temperatures.
合成酯被用作高温应用的润滑剂，但它们的开发可能是一个反复试验的过程。在这种情况下，分子动力学模拟可以用作研究新型润滑剂（特别是粘度）特性的工具。我们采用非平衡分子动力学（NEMD）模拟来预测两组酯（癸二酸二（2-乙基己基）酯（DEHS）和己二酸二（2-乙基己基）酯（DEHA））混合物在 293 K 和 343 K 下的牛顿体粘度以及在 393 K 下的平衡分子动力学（EMD）和 NEMD，并将这些模拟结果与实验测量值进行比较。模拟预测混合物密度与实验值相差在 5%以内，并且我们能够在所有温度范围内恢复所有混合物的 99%至 75%的实验粘度。实验粘度显示出线性趋势，我们能够使用低温下的 NEMD 和高温下的 EMD 来捕捉这种趋势。我们的工作表明，通过使用 EMD 和 NEMD 模拟以及我们开发的工作流程，我们可以在不同温度下可靠地估计工业相关酯基润滑剂混合物的粘度。
