Steam Flow Orifices

Overview

Engineering reference data for Steam Flow Orifices 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	—

Unit Conversions

The following conversion factors are essential for working with steam flow calculations across different unit systems.

Orifice Plate Application

Orifice plates are simple flow measurement devices. For steam systems, they are used to measure flow rate based on a known upstream pressure and a downstream condition, typically atmospheric pressure.

Example: Steam flow through a 1/4-inch (6.35 mm) orifice with an upstream line pressure of 50 psig (3.45 bar gauge) discharging to atmosphere is approximately 98 lb/h (0.0124 kg/s). This value is typically determined using standard engineering charts or formulas for sharp-edged orifices.

References

• Original Source