Experiments were performed to evaluate the heat transfer of monodisperse sprays of large droplet diameters, ranging from 3 to 25 mm, on high temperature surfaces. This range of drop sizes has not previously been studied, and it was of interest to determine their heat transfer characteristics and how they relate to sprays of smaller drops. Parametric tests showed that the spray heat flux depends on mass flux with a power-law relationship, and that spray effectiveness, which relates the actual spray heat transfer to the maximum heat transfer potential, varies with d−1/2. There was no discernible relationship between the heat transfer and droplet velocity. These results agreed favorably with published results for smaller droplets. The current data was compared to previous tests with smaller droplets using the droplet Reynolds and Weber numbers. This analysis showed some grouping, with a marked separation at We = 80, where the dynamic behavior of droplets has been shown to change for nonwetting impaction.

Issue Section:
Porous Media, Particles, and Droplets
Keywords:
Droplet, Heat Transfer, High Temperature, Thermophysical, Two-Phase
Topics:
Drops, Heat transfer, High temperature, Sprays, Water
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