Pool Boiling of Dilute Emulsions on Flat Surfaces

We report measurements of steady state boiling heat transfer in a dilute emulsion of FC72™ in water on upward and downward facing surfaces. Augmented heat transfer coefficients are expressed as a free convection regime followed by a significant increase when the surface temperature exceeds the saturation temperature of the disperse component. Augmented heat transfer coefficients reach three times that in free convection for all volume fractions at surface temperatures near the saturation temperature of the continuous component, followed by a rapid decrease as film boiling commences. For the downward facing surface, the augmentation effect is seen when the surface temperature approaches the saturation temperature of the continuous component. At that point, the presence of the disperse component produces a doubling of the heat transfer coefficient.