A model for the simulation of an atomizing, vaporizing liquid spray, such as the one present in the Space Shuttle Main Engine fuel-side preburner is presented. Flow equations are solved using a two-phase approach, with liquid droplets functioning as one phase, and multicomponent gas as the other. Specific attention is given to models used to describe the dependence of surface tension on temperature around the critical point. Most liquids at subcritical temperatures tend to exhibit a nonlinear drop in surface tension with increasing temperature, with the surface tension vanishing at the critical temperature. This phenomenon can have significant effects on prediction of liquid spray breakup, mixing, and combustion. A computer code, KIVA-II, which was developed at Los Alamos National Laboratory was modified to allow for the use of liquid oxygen sprays possessing surface tension described by three different functions of temperature. Results are obtained for the velocity field, droplet Sauter mean radius, species concentration, and temperature, and examined for sensitivity to different surface tension models. The results show substantial dependence of the atomization, vaporization, and diffusion processes upon the specific surface tension representation, and confirm the importance of selecting the proper surface tension model for accurate prediction of spray breakup processes.