Molecular dynamics simulation of freezing point and viscosity-temperature relationship of aviation kerosene
CHEN Xuejiao, HOU Lei, LI Shiyao
National Engineering Laboratory for Pipeline Safety/ MOE Key Laboratory of Petroleum Engineering /Beijing Key Laboratory of Urban Oil and Gas Distribution Technology, China University of Petroleum-Beijing, Beijing 102249, China
Freezing point and viscosity-temperature relationship are important quality indexes for evaluating low temperature fluidity of aviation kerosene. A kerosene model composing of 5 alkane molecules was established based on a carbon number distribution, carbon/hydrogen mass ratio and aromatic hydrocarbons/saturated hydrocarbons mass ratio. The kerosene model was studied by molecular dynamics simulation. Freezing point was predicted according to the sudden change of density-temperature and diffusion coefficient-temperature curves and the simulated freezing point is consistent with the experimental value. The radial distribution function was simulated to analyze the microstructure of kerosene modelled at temperatures close to freezing point. The results showed that aggregation between like molecules was the main reason that influenced the freezing point. Aromatic hydrocarbons had greater influence than saturated hydrocarbons on the freezing point. The Rouse Model was employed to study the viscosity-temperature relationship of the kerosene model. The simulated viscosity index was identical to test data, showing good agreement between simulated and experimental viscosity changes with temperature.
