A molecular dynamics simulation study of the densities and viscosities of 1,2,4-trimethylbenzene and its binary mixture with n-decane

XM Yang and Q Liu and XZ Zhang and C Ji and BY Cao, FLUID PHASE EQUILIBRIA, 562, 113566 (2022).

DOI: 10.1016/j.fluid.2022.113566

N-decane and 1,2,4-trimethylbenzene (1,2,4-TMB) are components of many hydrocarbon aviation fuels and surrogate fuels. Obtaining and understanding their physical properties is crucial for their practical applications. In this study, the viscosities and densities of pure 1,2,4-TMB and its binary mixture with n-decane are investi-gated by equilibrium molecular dynamics (EMD) simulations with the COMPASS force field. The simulation results are compared with the predictions of several theoretical models: the modified Peng-Robinson (MPR) equation, Grunberg-Nissan (GN) model and UNIFAC-VISCO (UV) model for viscosity and the Peng-Robinson (PR) equation and the Tait equation for density, using NIST SUPERTRAPP data as a reference. Results show that the sixth-order mixing rules for MD simulations with the COMPASS force field provide a better prediction accuracy than the Lorentz-Berthelot mixing rules. The MD simulation results are in good agreement with the NIST SUPERTRAPP data, and the MD simulation model achieves better accuracy than the compared theoretical models. The self-diffusion coefficients of the components in the mixture are calculated and a comprehensive structural analysis is carried out to produce a better understanding of the effect of temperature on the viscosity and density of the binary mixture at a molecular level.

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