Thermodynamic Analysis of Quasi-Steady Evaporation of Suspended Binary Liquid Fuel Droplets in a Mixed Convective Environment
S. Raghuram and Vasudevan Raghavan
This study presents a thermodynamic model for predicting the vaporization characteristics of multi-component hydrocarbon fuel droplets under low pressure, mixed convective conditions. The model employs activity coefficients based on UNIFAC group contribution method and evaluates the vapour-liquid equilibrium of the droplet. The gas-phase properties have been evaluated as functions of temperature and mixture molecular weight. The model has been compared and validated with the experimental data from literature. The validated model is used to predict the vaporization characteristics of binary n-heptane-n-decane droplet blends at atmospheric pressure under natural convection followed sequentially by forced convection. Results show that the duration of natural convection, influences the vaporization characteristics during forced convection. It was also observed that the blend composition and ambient temperature greatly influence the evaporation behaviour, while the freestream velocity has only a mild influence on it.
Keywords: Droplet vaporization, natural convection, forced convection, mixed convection, binary fuel droplet, vapour-liquid equilibrium, activity coefficient.