Abstract:
Nucleate boiling is the preferred mode of boiling. An experimental setup for studying
nucleate pool boiling of water with surfactant additive is developed. Sodium oleate is used
as surfactant additive. Saturated nucleate pool boiling of both water and water with sodium
oleate on a horizontal cylindrical heater surface has been investigated experimentally.
Cartridge type electric heater with provision of surface temperature measurement is
employed for heat generation. Change of heat flux with wall superheat is measured and
change of heat transfer coefficient with wall superheat is calculated. The experimental
results show that a small amount of surfactant enhances the heat transfer coefficient
significantly. At low surfactant concentrations, heat transfer coefficient increases with
increasing surfactant concentration in water. The maximum heat transfer enhancement is
found to be at 250 ppm of sodium oleate solution. By adding more surfactant to water, heat
transfer coefficient is found to be lowered. Surface tension of different concentration of
sodium oleate solutions is measured. It is observed that the maximum heat transfer
coefficient is obtained at a surfactant concentration that corresponds to the critical micelle
concentration (cmc) of the surfactant/water solution.
