Recommendations
Circular weirAtmospheric pressure given altitudeHazen-Williams equation head lossAir specific massDynamic viscosity of atmospheric airHydrofoil turbine floculator
Head loss coefficient applicable to partially open gate and knife gate valves
Default

Input data

Diameter (D) or height (H)

Opening ratio

Output data

k for knife gate valve

kQ for knife gate valve

k for gate valve

kQ for gate valve

Description

Find the head loss coefficients for partially open gate and knife gate valves.

Given the diameter and the opening relation of a gate valve, or the side and the opening relation of a knife gate valve, calculates the head loss coefficients, for the expressions hf = k.U²/2g and ℎf = kQ.Q².

  • For k applicable to:
    hf=k⋅U22⋅g hf = \frac{k \cdot U^2}{2\cdot g}
  • For kQk_Q applicable to:
    hf=kQ⋅Q2 ℎf = k_Q\cdot Q^2

Gate valve

References

  • Miller, Donald S. Internal flow systems. BHRA Fluid Engineers, 1978.