| Abstract: | The rising of droplets in water contaminated with two surfactants, sodium salt dodecylhydrogenosulphate (L.S.S.) and Teepol, in the range 200 < NRep < 1000 was studied. The dispersed phases used were cyclohexane, benzene, toluene, and n-heptane. Experiences were conducted at a constant temperature of 30°C. It was shown that the presence of the two agents decreases the final rising rate of the droplets with an increasing surfactant concentration and droplet diameter. For the same interfacial tension values, this phenomenon is enhanced in the case of Teepol. An equation is proposed for the computation of the critical droplet diameter as well as the droplet rising rate. These equations demonstrate the effect of the chemical nature of the surface agent and reproduce the experimental results with variations less than 10%. |
