Suspended droplet evaporation modeling in a laminar convective environment

A detailed numerical model is used to analyze the evaporation characteristics of a fuel droplet which is suspended concentrically from a spherical bead born at the tip of a thin cylindrical filament. The suspended droplet is exposed to a high-temperature, laminar, gaseous stream with a relevant Reynolds number Re not, vert, similar 50. The model solves the time-dependent axisymmetric Navier-Stokes and energy equations in both fluid phases, in conjunction with the heat conduction equation within the suspender material. The various mechanisms through which the suspender affects the heat and mass transport processes in the droplet interior are evaluated. The effects of suspender size and material are investigated at a pressure typical of gas-turbine combustor environments. The model predictions indicate that when quartz suspenders are implemented to determine liquid-fuel evaporation characteristics, the droplet surface regression rates do not vary appreciably with suspender sizes. The results also show that mean surface temperatures of free-traveling droplets are fairly well represented by those of suspended stationary droplets exposed to identical ambient conditions. However, the suspended-droplet configuration overestimates liquid evaporation rates of free-convecting droplets, thus underpredicting droplet lifetimes.