Orifice Flow Rate Equation

Orifice Flow Rate Formula:

\[ Q = C_d \times A \times \sqrt{\frac{2 \times \Delta P}{\rho}} \times 448.83 \]

Discharge Coefficient (C_d):

Area (A):

ft²

Pressure Difference (ΔP):

psi

Density (ρ):

lb/ft³

Flow Rate (Q): GPM

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Orifice Flow Rate Equation?

Definition: This equation calculates the volumetric flow rate through an orifice based on the pressure difference across the orifice.

Purpose: It helps engineers and technicians determine fluid flow rates in piping systems, hydraulic systems, and other fluid applications.

2. How Does the Equation Work?

The equation is:

\[ Q = C_d \times A \times \sqrt{\frac{2 \times \Delta P}{\rho}} \times 448.83 \]

Where:

\( Q \) — Flow rate (gallons per minute, GPM)
\( C_d \) — Discharge coefficient (dimensionless, typically 0.6-0.65 for sharp-edged orifices)
\( A \) — Cross-sectional area of the orifice (square feet)
\( \Delta P \) — Pressure difference across the orifice (psi)
\( \rho \) — Fluid density (pounds per cubic foot)
448.83 — Conversion factor to get GPM

Explanation: The equation relates flow rate to the square root of the pressure drop, accounting for fluid properties and orifice characteristics.

3. Importance of Orifice Flow Calculation

Details: Accurate flow rate calculations are essential for system design, performance evaluation, and troubleshooting in fluid systems.

4. Using the Calculator

Tips: Enter the discharge coefficient (default 0.62), orifice area in ft², pressure difference in psi, and fluid density in lb/ft³ (default 62.4 for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical discharge coefficient value?
A: For sharp-edged orifices, 0.62 is common. The value varies with orifice geometry and Reynolds number.

Q2: How do I convert orifice diameter to area?
A: Area = π × (diameter/2)². Remember to convert inches to feet if needed (divide by 12).

Q3: What density should I use for other fluids?
A: Use 62.4 lb/ft³ for water. For other fluids, check their specific gravity or density tables.

Q4: Why is the flow proportional to the square root of pressure?
A: This relationship comes from Bernoulli's equation and reflects the conversion between pressure and velocity energy.

Q5: Does this work for compressible fluids (gases)?
A: No, this equation is for incompressible fluids. Gas flow requires different calculations accounting for compressibility.