Kvwaarde

Kvwaarde, or Kv-waarde, is the flow coefficient of a valve used in hydraulics and process engineering. It quantifies how much water can pass through a valve for a given pressure drop. The standard relation is Q = Kv × sqrt(Δp), where Q is the volumetric flow rate (typically in cubic meters per hour) and Δp is the pressure drop (in bar). At a pressure drop of 1 bar, Q equals Kv in m^3/h. The Kv value depends on the valve size, type, and its opening position.

Kvwaarde is a key parameter in valve sizing and system design. It is used in heating, ventilation and air conditioning, water supply, and process industries to ensure that a valve provides the required flow at the expected pressure loss. Manufacturers publish Kv values for different valve sizes and positions, enabling engineers to select components that meet system performance criteria.

Relation to Cv: Kv is the metric counterpart of the Imperial Cv coefficient. The two are related by a conversion factor, depending on units. A commonly used approximation is Cv ≈ 1.156 × Kv, or equivalently Kv ≈ 0.865 × Cv. This meansCv (in US customary units) and Kv (in metric units) describe similar flow behavior, but under different unit systems.

Limitations and scope: Kv is defined for incompressible liquids like water near standard conditions. For fluids with different viscosity or density, or for gases and compressible flows, Kv-values must be adjusted or recalculated. Temperature, fluid properties, and valve characteristics such as turbulence and leakage can affect actual flow compared to the Kv-based prediction.