Validating formulas for the prediction of ascent speed and mass transfer coefficient for liquid oil droplets and gas bubbles under pressure
Several different formulas exist to predict the ascent speed of gas bubbles and oil droplets released in deep waters. Similarly, different formulas are also available to predict the mass transfer coefficient of compounds dissolving into water during ascent. However, the formulas used by different authors for the modeling of the ascent and mass transfer processes of liquid oil droplets or gas bubbles under pressure can lead to widely different predictions. In this work, we investigate the abilities of different formulas to reproduce literature laboratory data for the ascent speed and mass transfer coefficient for liquid droplets and gas bubbles under pressure. We found that the ascent speed is usually well predicted by a combination of formulas by Clift et al. (1978) or by the Fan-Tsuchiya equation, with mean errors <20% and <25% for liquid CO2 droplet data by Bigalke et al. (2007). The mass transfer coefficient describing transfer of material from “dirty” droplets to water is well reproduced for droplets with diameters in the range 1.5-4 mm by a set of formulas presented in Clift et al. (1978), based on data from Thorsen and Terjesen (1962) for droplets constituted of a mixture of benzene and chlorobenzene. The formula of Kumar and Hartland (1999) behaves satisfactorily for clean droplets.
Record created on 2016-02-22, modified on 2016-12-27