Siserõhk

Siserõhk, also known as passing pressure or transient pressure, refers to the temporary increase in pressure within a fluid system, often observed during rapid changes in flow conditions such as valve closures, pump startups, or sudden pipe movements. It is a specific form of hydraulic pressure spike that occurs when the momentum of the moving fluid is abruptly altered, causing a shock wave that propagates through the piping system.

This phenomenon is a significant consideration in the design and operation of hydraulic and piping systems, as excessive siserõhk can lead to pipe damage, leaks, or failures. Engineers utilize various methods to mitigate it, including installing shock arresters, pressure relief valves, and expansion tanks. Properly designed pipeline systems take into account the potential for siserõhk by selecting appropriate pipe materials, thicknesses, and valve operations to absorb or dissipate these pressure surges.

The magnitude of siserõhk depends on factors such as fluid velocity, pipe length, elasticity of the piping material, and the rate of change of flow. It is often calculated using the Joukowsky equation, which relates the pressure increase to the fluid density and the change in velocity during flow interruption:

ΔP = ρ * c * ΔV

where ΔP is the pressure increase, ρ is the fluid density, c is the speed of pressure wave in the fluid, and ΔV is the change in velocity.

Understanding and managing siserõhk is crucial in many industrial applications, including water supply, chemical processing, and energy generation, to ensure system integrity, safety, and durability.