Hello Prashanth (and Other Field Experts),

To be more specific, I have added page numbers where gas-liquid mass transfer formula is given. 

https://doi.org/10.1016/j.ces.2007.01.065         (Page-7, left column)

https://doi.org/10.1016/j.ces.2018.01.009         (Page-4, at bottom right corner)

https://www.hzdr.de/publications/PublDoc-10321.pdf        (Page-9, at the bottom)

https://ris.utwente.nl/ws/portalfiles/portal/5529968/numerical_modeling.pdf      (Page-4, left column)

Any lead? whether volume fraction of phase should appear or not in mass transfer rate?

Kindly respond