Add a Mass Transfer node to include mass transfer from the gas to the liquid.

Select a Mass transfer model — Two-film theory, Nonequilibrium model, or User defined. For User defined enter a value or expression for the Mass transfer from gas to liquid mgl (SI unit: kg/(m3·s)). The default is 0 kg/(m3·s).

For Nonequilibrium model enter values or expressions for each of the following:

For Two-film theory enter values for the Mass transfer coefficient k (SI unit: m/s), Henry’s constant H (SI unit: Pa·m3/mol), the Dissolved gas concentration c (SI unit: mol/m3), and the Molecular weight of species M (SI unit: kg/mol). Refer to the theory below for more information.

Henry’s law gives the equilibrium concentration c* of gas dissolved in liquid:

where H is Henry’s constant. The molar flux per interfacial area, N (SI unit: mol/(s·m2)), is determined by

where k is the Mass transfer coefficient and c is the Dissolved gas concentration in liquid.

The mass transfer from gas to liquid, mgl, is given by

where M is the Molecular weight of species and a is the interfacial area per volume (SI unit: m2/m3).