Droplet Vaporization and Secondary Breakup at High Temperature and Pressure in Uniform and Non-Uniform Flow Fields

摘要

A model describing the vaporization of hydrocarbon droplets at high-pressure and temperature in non-uniform flow fieldsrnhas been developed. This model is used to investigate the effect of ambient conditions similar to those found in dieselrnengines on droplet secondary breakup as characterized by a Weber number criterion. The droplet vaporization rate isrncalculated using an extended film model and the spherically symmetric energy equation is solved to obtain the evolution ofrnthe radial temperature distribution in the droplet. The high-pressure phase equilibrium at the droplet surface is evaluatedrnby equating the fugacity of each species in each phase, as obtained from a Peng-Robinson equation of state. Furthermore,rnan advanced, composition-dependent surface tension model is implemented. Various background flows are then used, viarnone-way coupling, to investigate the effect of parameters such as ambient pressure and droplet initial diameter on dropletrnhistory and its propensity to breakup.