It was of great significance correctly to predict the vapor diffusion and emission inside the tank for the researches of gasoline evaporation loss and vapor pollution control during the operation of loading gasoline into a tank. Then

two key parameters of the volumetric ratio λ of the displacement mixture gas of the vapor-air to the loaded gasoline and the qualitative ratio η of the evaporation loss to the loaded gasoline were mainly considered. Based on the models of volume of fluid(VOF)

mass transfer and RNG k-ε turbulence

the evaporation loss was numerically simulated and experimentally investigated during the splash loading operation

and the oil vapor-air diffusion was analyzed and compared for the different loading exit heights

different loading velocity and the different initial vapor mass fraction. Meanwhile

an experimental system of evaporation loss in loading into a tank was built up to verify the numerical simulation

and the results of the numerical simulation were agreed well with the experimental data. The simulation results furthermore showed that the higher of the loading exit

the greater the qualitative ratio η of the evaporation loss to the loaded gasoline. The qualitative ratio of high exit was at around 0.34% and the qualitative ratio of low exit at around 0.025% by the increase of the loading velocity. The qualitative ratio η of high exit was at around of 0.44%

the qualitative ratio of mid exit at around 0.21% and the qualitative ratio of low exit at around 0.043% by increasing the initial vapor mass fraction. It was recommended that the effect of loading velocity and the initial vapor mass fraction should be considered in API loss formula by using a clean tank and low exit when loading and reducing loading speed appropriately before the loading pipe exit was submerged.