Tubular pinch effect

As a pinch effect (English: to pinch = pinch ) is a phenomenon of fluid dynamics called, that is, among other things in the membrane technology is important.

Mark C. Porter suspected as the first, that the so-called pinch effect is responsible for the return of separate particles from the membrane into the core flow ( also with under Tubular Pinch effect). 1956 was proved by G. Segre and A. Silberberg when working with dilute suspensions of spherical particles in pipelines for the first time this effect. When flowing through Selbiger the particles apparently wandered away from the tube wall and the tube axis, reaching a balance in an eccentric radial position.

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This effect is in the membrane technology for cross -flow filtration, especially of importance in dialysis. He plays especially for particles with a diameter of 5 microns and laminar flow conditions a role and slowed the process of filter cake formation, the operating lives and the filtering keeps permanently high.