Thick Exchange Layer Evaporation Model with Natural Convection Effect for Multicomponent Droplet and Its Validation

In order to develop the high temperature evaporation model for multicomponent liquid fuel, based on zero-diffusion/infinite diffusion concept, thick exchange layer evaporation model with natural convection effect is expanded to multicomponent liquid fuels and multicomponent NC-TEL model is proposed. Then suspended single droplet evaporation characteristics of three kinds of blended fuel: n-heptane-ethanol, n-decane-ethanol, RP-3 aviation kerosene-ethanol were experimentally studied in high temperature air environment with and without forced convection. The experimental results show that the droplet evaporation rate value increases significantly along with the increase of ambient temperature. And the higher the temperature is, the more significant the composition ratio is to the droplet evaporation rate. The effects of forced convection on droplet evaporation are not very obvious in the condition in this paper. Finally, the model was validated by experimental data. The model comparison results show that on the whole, NC-TEL model behaves better than R-M model, and the prediction accuracy in high temperature test section is improved by 8% to 35% on average. In the lower temperature test section, the zero-diffusion NC-TEL model is in good agreement with the experimental results, while the infinite diffusion NC-TEL model has a certain error. In high temperature test section, for n-heptane-ethanol droplet, the predictions of NC-TEL model are accurate. But for n-decane/RP-3 aviation kerosene-ethanol, the prediction values of NC-TEL model are lower, and possible causes are the microexplosion phenomenon and the Marangoni phenomenon. © 2019, Editorial Department of Journal of Propulsion Technology. All right reserved.