Pool Boiling Heat Transfer of Aqueous Surfactant Solutions

Experiments were conducted to investigate the nucleate pool boiling heat transfer characteristics and steam carrying phenomena during boiling for different aqueous surfactant solutions, 99% sodium dodecyl sulfate(SDS) and Triton X-114. Bubble behaviour, heat transfer enhancement mechanisms and steam carrying phenomena were discussed for a range of heat flux (24.7-109.1 kW/m2) and mass concentrations (50-8000 ppm for SDS and 20-1000 ppm for Triton X-114). The bubble observations show that, when compared with water, boiling in surfactant solutions is observed to be more vigorous with smaller-sized and fast departure frequency. The surfactant solutions of Triton X-114 is becoming cloudy during boiling at around cmc for its cloud point is much lower than the boiling liquid temperature. The experiments of boiling heat transfer conclude that an optimum heat transfer enhancement is achieved near the critical micelle concentrations (cmc) of the surfactants, and at the same heat flux, the optimum boiling heat transfer enhancement at cmc of SDS is higher than that of Triton X-114 when compared with pure water. The enhancement of boiling heat transfer by the addition of surfactants is the complex effects of surfactant species, the reduction of surface tension, the changes of the contact angel. The experiments of steam carrying show that the amount of surfactants which carried out by steam from solutions during boiling dependeds on the species of surfactant, heat flux and concentration of the initial surfactant aqueous solutions.