Droplet vaporization characteristics of multicomponent mixtures of methanol and gasoline surrogate in opposed stagnation flows

Abstract

This paper develops and applies a model to characterize the vaporization of gasoline–methanol blends in applications such as homogeneous direct injection spark ignition (DISI) engines. In DISI engines, the fuel is injected during intake or early in the compression stroke. Thus, the fuel droplets must vaporize in a low-temperature environment. Because methanol’s relatively high latent heat, the gases cool significantly during vaporization. Opposed stagnation flow is a computationally efficient platform on which to base the study. The study predicts the effects of initial droplet size, temperature, fuel–air ratio, methanol fraction, and operating pressure. Results include liquid- and gas-phase profiles during the vaporization process. Parameter studies show the state of the droplets, the gas phase temperature, and composition near the end of the droplet’s lifetime. The results provide quantitative insight about optimizing ignition and combustion, including under engine cold-start conditions.