property>mass transfer coefficient

What is a Mass Transfer Coefficient?

The mass transfer coefficient determines the rate of mass transfer across a medium in response to a concentration gradient. It is an important principle in fluid dynamics and chemical engineering, especially in the design of fluid contact equipment such as gas scrubbers.

Mass transfer coefficients are usually obtained by semi-empirical methods. These combine a theoretical analysis of the problem using mathematical analogies and frequently guesses based on dimensional analysis, in combination with experimental data.

There are two main mechanisms depending on whether the flow is laminar or turbulent. In laminar flow (or in the absence of flow) the process of mass transfer is mainly due to molecular diffusion. If turbulent flow is involved the turbulent eddies act as a transport mechanism giving rise to transport rates that may be orders of magnitude higher than those due to molecular effects.