Inputs
For incompressible, non-flashing liquid service using the basic liquid Cv relation. For viscous, flashing, cavitating, two-phase, gas, or steam service, use a full valve-sizing method and manufacturer data.
Results
Cv
—
Kv
—
Flow rate
—
Pressure drop
—
Equation
Q(gpm) = Cv √(ΔP(psi) / SG)
The US Cv definition uses US gallons per minute and psi. Kv is also reported using the conversion Cv = 1.156099 Kv. This simple equation does not include corrections for high viscosity, choked liquid flow, flashing, cavitation, piping geometry factors, or valve-specific recovery behavior.