Flow Coefficient Factor

Overview

Engineering reference data for Flow Coefficient Factor in fluid mechanics.

Key Formulas

Reynolds Number

$Re = \frac{\rho v D}{\mu}$

Ratio of inertial to viscous forces — determines flow regime.

Bernoulli's Equation

$P + \frac{1}{2}\rho v^2 + \rho g h = \text{const}$

Conservation of energy for steady, inviscid, incompressible flow.

Continuity Equation

$A_1 v_1 = A_2 v_2$

Conservation of mass for incompressible flow.

Darcy-Weisbach

$\Delta P = f \frac{L}{D} \frac{\rho v^2}{2}$

Pressure drop due to friction in a pipe.

Variables

Symbol	Description	Unit
$Re$	Reynolds number	—
$\rho$	Fluid density	kg/m³
$v$	Flow velocity	m/s
$D$	Characteristic dimension	m
$\mu$	Dynamic viscosity	Pa·s
$P$	Pressure	Pa
$f$	Darcy friction factor	—

Cv to Kv Conversion

The flow coefficient (Cv) and flow factor (Kv) are related by a fixed conversion factor. The formulas are:

$C_v = 1.16 \cdot K_v$ $K_v = 0.862 \cdot C_v$

Key Notes:

• Cv is defined for water at 60 °F (15.6 °C).
• Kv is defined for water in the range 5 - 30 °C.
• When performing calculations, ensure all other parameters (pressure drop, flow rate, fluid properties) are consistent with the chosen coefficient's unit system (Imperial for Cv, SI for Kv).

References

• Original Source