Paineenhäviö

Paineenhäviö refers to the reduction in fluid pressure that occurs as the fluid flows through a system. This phenomenon is a fundamental concept in fluid mechanics and engineering. It arises from several factors, primarily friction between the fluid and the conduit walls, and also from changes in the fluid's velocity and direction.

In a simple pipe flow, the primary cause of pressure loss is viscosity, which leads to shear stress at the pipe walls. This friction converts some of the fluid's mechanical energy into heat, resulting in a decrease in pressure along the flow path. The magnitude of this pressure loss is influenced by the fluid's viscosity, density, the pipe's diameter, length, and surface roughness. Higher viscosity, longer pipes, smaller diameters, and rougher surfaces all contribute to greater pressure loss.

Another significant contributor to pressure loss is turbulence. When fluid flow becomes turbulent, rather than smooth and laminar, chaotic eddies and swirling motions develop. These irregularities dissipate energy and lead to a more substantial pressure drop than would occur in laminar flow under similar conditions. Fittings, valves, bends, and sudden changes in pipe diameter also introduce localized pressure losses due to the disruption of smooth flow patterns. These are often referred to as minor losses, though they can be significant in systems with many such components. Understanding and quantifying pressure loss is crucial for designing efficient fluid systems, such as pipelines, hydraulic circuits, and HVAC systems, as it directly impacts the energy required to move the fluid.