Kapillærgennemstrømningen

Kapillærgennemstrømningen, also known as capillary flow, refers to the movement of liquids through narrow channels or porous materials driven by capillary forces. These forces arise from the interplay between adhesive forces between the liquid and the solid surface, and cohesive forces within the liquid itself. When the adhesive forces are stronger than the cohesive forces, the liquid will tend to wet the surface and rise or spread within the capillary.

The phenomenon is governed by the Young-Laplace equation, which relates the capillary pressure to the surface tension of the liquid and the curvature of the liquid-solid interface. The smaller the radius of the capillary or pore, the greater the capillary pressure and thus the stronger the driving force for liquid movement. This is why the term "capillary" is used, referring to very fine tubes.

Capillary flow is a fundamental process observed in a wide range of natural and technological applications. In biology, it plays a crucial role in water transport in plants, allowing water to move from the soil up through the xylem vessels to the leaves against gravity. It is also involved in the movement of blood through capillaries in the circulatory system.

In materials science and engineering, capillary flow is exploited in processes such as ink-jet printing, where ink is propelled through fine nozzles. It is also important in the absorption of liquids by porous materials like paper, textiles, and soil. Understanding and controlling capillary flow is essential for optimizing these processes and developing new technologies.