Transferkoeffizient

Transferkoeffizient, often translated as transfer coefficient, is a parameter used in transport phenomena to quantify the rate at which a quantity is transferred across a boundary or between phases. It expresses the proportionality between a flux or transfer rate and its driving force. In its simplest form, the relation can be written as J = k X, where J is the flux of the carried quantity, X is the driving force (for example, a concentration difference, a temperature difference, or a velocity difference), and k is the Transferkoeffizient. The value and sometimes the dimension of k depend on what is being transferred and on the system’s geometry and flow conditions.

In chemistry, chemical engineering, and physics, transfer coefficients describe mass transfer, heat transfer, and momentum transfer. For mass transfer, the molar flux N may be expressed as N = k_m (C_A,bulk − C_A,interface) or, in overall form, N = k_G A (C* − C_bulk). For heat transfer, the heat flux q relates to temperature difference via q = h A (ΔT), defining the heat transfer coefficient h. In fluid mechanics, coefficients describe the transfer of momentum, such as shear stress related to velocity gradients.

Coefficients are typically determined empirically or via semi-empirical correlations, often using dimensionless groups like the Sherwood, Nusselt, and Reynolds numbers. They depend on temperature, pressure, geometry, and flow regime. Transferkoeffizienten are essential for designing equipment such as heat exchangers, distillation columns, membranes, and reactors, where accurate prediction of transport rates governs performance and efficiency.