Investigation of mass transfer in milli-channels using high-resolution microfocus X-ray imaging

The experiments covered a large range of initial Taylor bubble length varying from 5 to 22 mm. The results show that the measured Sherwood numbers depend strongly on the bubble length and also equivalent diameter, which is the same trend as in previously reported results for larger pipe sizes. However the values of measured Sherwood numbers could not be predicted by available correlations. As a result a new mass transfer coefficient in the form of Sherwood number and as a function of Peclet number as well as the ratio of bubble equivalent diameter to capillary diameter (deq/D) is presented. The proposed correlation is applicable for a large range of the ratio deq/D that varies from 0.8 to 1.6. The average relative error between measured Sherwood number and the one calculated with the new correlation is less than 9.6%.