Saturated flow boiling heat transfer of environmentally acceptable surfactants

Saturated flow boiling of surfactant solutions was studied and compared to that of pure water. The liquid flowed in an annular space between two vertical tubes. The heat was transferred from the inner heated tube to the outer one. A nonionic surfactant, with negligible environmental impact, was used. The surface tension for the water–surfactant system was determined at various temperatures. High-speed photography was used for direct observation of the sequence of events that occur during flow boiling. The heat transfer experiments focused on the saturated boiling regime. Addition of surfactant to water produced a large number of small diameter bubbles, which, at high heat fluxes, tend to cover the entire heater surface with a vapor blanket. Boiling heat transfer coefficients in surfactant solution are higher than that in pure water.