upward flow

An upward flow refers to a flow in which a fluid or a solid-fluid mixture moves predominantly upwards against the force of gravity.

In process engineering, the term ‘upward flow’ is used, for example, when a gas or liquid flows from the bottom upwards through a bed of material, a pipe or a vessel. This allows solid particles to be carried along, kept in suspension or classified. In mixers with a vertical flow direction – such as those with helical mixing elements – upward flow describes the main upward component of the flow within the mixed material bed. The interaction between upward and downward flows then determines the circulation, the residence time distribution and the achievable mixing quality.