Hinterland ratio

The hinterland ratio is a dimensionless number from technical chemistry . It describes the relationship between liquid volume and boundary layer volume in two-phase systems . The hinterland ratio is generally defined as:

${\displaystyle Hl={\frac {V_{L}}{V_{G}}}=B^{-1}}$

The following equation is often used in practice:

${\displaystyle Hl={\frac {(1-\epsilon _{G})\beta _{1,L}}{aD_{1,L}}}}$

• ${\displaystyle \epsilon _{G}}$ Gas share (hold-up),
• ${\displaystyle \beta _{1,L}}$ Mass transfer coefficient ,
• ${\displaystyle a}$ specific surface ,
• ${\displaystyle D_{1,L}}$ Diffusion coefficient of component 1 in the fluid phase.

A small hinterland ratio means that the boundary layer volume is large in relation to the total volume. This is the case, for example, with fine atomization of the liquid phase in the gas phase. A high hinterland ratio occurs, for example, when the liquid phase is bubbled through with the gas phase.