In this section various correlations that are used to estimate the convective mass transfer coefficients for various cases are presented. The various correlations are generally formed in terms of different dimensionless groups associated with the mass transfer. The definitions of mostly useful dimensionless groups associated with the mass transfer are given in Table 3.1 as follows:

Mass transfer coefficients for a single sphere in case of natural convection

In presence of natural convection the mass transfer from single sphere were studied by Steinberger and Treybal (1960) and they recommended the mass transfer coefficient as follows:

Correlation of mass transfer coefficients for flat plates

There are several investigations in literature regarding the evaporation from a free liquid surface or the sublimation from a flat solid surface into air stream under both laminar and turbulent conditions. Wilty et al. (1984) developed correlations for the average mass transfer coefficient during evaporations from a flat solid surface of characteristic length of L under laminar and turbulent conditions as follows: