Plug flow

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A plug flow (ger .: plug flow , even plug flow ) is in fluid dynamics flow in a pipe , in which the flow rate is almost equal throughout the flow cross section. It only shows a sudden drop in speed directly on the pipe wall. Figuratively speaking, the medium then moves like a plug in a pipe.

The plug flow is in contrast to the parabolic flow profile , which forms in the laminar flow of an ideally viscous ( Newtonian ) liquid. In such a parabolic flow profile, the local shear in the pipe center tends to zero and is maximal at the wall.

A transition from plug to parabolic flow occurs when the viscosity of the material decreases towards the wall, e.g. B. by shear thinning .

Reaction engineering

Scheme of a tubular reactor in which a plug flow is assumed.

The flow in a tubular reactor can be idealized as a plug flow . The dwell time of each volume element is then the same, and concentration gradients only occur in the direction of flow.

supporting documents

  1. ^ E. Fitzer, W. Fritz, Technical Chemistry - Introduction to Chemical Reaction Engineering , Springer, Berlin, 1989, pages 66f, 78.