Multicomponent-Fuel Film-Vaporization Model for Multidimensional Computations

Abstract

A multicomponent-fuel e lm-vaporization model is developed to be used in multidimensional spray and combustion computations. For the gas phase the vaporization rate was evaluated using the turbulent boundary-layer assumption and the Prandtl mixing-length theory. A third-order polynomial was used to model the temperature and species concentration proe les within the liquid e lm in order to predict accurate surface temperature and surface mass fractions, which are crucial to evaluating the species vaporization rates. By this approach the governing equations for the e lm were reduced to a set of ordinary differential equations. The new model offers a signie cant reduction in computational cost and sufe cient accuracy compared to solving the governing equations for the e lm directly. The new model was verie ed against exact numerical solutions with excellent agreement for several cases concerning the vaporization process of a e lm on a e at plate. The results were also compared with the solutions obtained using an ine nite-diffusion model. The new model predicted the vaporization history more accurately than the ine nite-diffusion model. Finally, the new model was applied to study the e lm evolution for a spray/wall impingement case, and physical insight was gained from the study.