Based on the hydrocarbon fuel characteristics of internal combustion engine, a molecular dynamics model of phase transition for n-dodecane (C12H26) droplets under sub/supercritical nitrogen atmosphere was established. The droplet temperature was compared with the existing research results to verify the reliability of the model. The changing laws which the gas-liquid interface thickness, the square of droplet diameter, the mean square displacement (MSD) and the diffusion coefficient of C12H26 droplet changed with the ambient pressure, temperature and time respectively in a supercritical environment were analyzed. The results show that when the ambient temperature and pressure is higher than the corresponding critical value of C12H26, with the increase of time, the square of droplet diameter is not proportional to time, the interface thickness of droplet increases from 18.43Å to 23.25Å, MSD increases linearly from 3.4×104 Å2 to 6.5×104Å2, the diffusion coefficient increases from 2.8×10－3 cm2/s to 4.37×10－3 cm2/s, the droplet phase change no longer obeys the d2 law, and the droplet changes from surface evaporation to the process of mixing and mutual dissolution dominated by diffusion.
TANG Chunyi
,
WANG Zhong
,
LI Ruina
,
LIU Shuai
,
LI Lilin
. Phase Transition Process of N-Dodecane Droplets under Sub/Supercritical Environment[J]. Vehicle Engine, 2021
, 0(1)
: 63
.
DOI: 10.3969/j.issn.1001-2222.2021.01.011
