Molecular dynamics simulation of thermophysical properties of binary RP-3 surrogate fuel mixtures containing trimethylbenzene, n-decane, and n-dodecane

Trimethylbenzene (TMB), n-decane, n-dodecane and their mixtures are commonly used in surrogate fuel of aviation kerosene. To date, molecular dynamic studies on the thermophysical properties of TMB and their mixtures are very few. In this study, equilibrium molecular dynamics (EMD) simulations with the TraPPE-UA force field are carried out to simulate the densities and thermal conductivities of Rocket Propellant-3 (RP-3) aviation kerosene surrogate mixtures, C10 + 1,2,4-TMB and C10 + C12, under sub/supercritical pressure. Results show that the simulated densities and thermal conductivities of TMB and the mixtures are in good agreement with the NIST data, and the two surrogate models can provide reasonable surrogate accuracy in predicting the thermophysical properties of aviation kerosene RP-3. The analysis of radial distribution functions, angular distribution functions, end-end length and dihedral angle distributions is carried out to better understand the temperature effect on the structure and thermophysical properties of the surrogates. It is found that the n-decane chains become shrinking and more twisted with the increasing of the temperature which reduce the thermal conductivity of the surrogates. This research offers a good reference for the analysis thermophysical properties of n-alkanes and TMB-based fuels.