How to Calculate Orifice Flow

The orifice flow calculator determines the flow rate of liquid through an orifice using the formula:

Orifice Flow Equation (Volumetric Flow Rate):

Where:

• \( Q \): Flow rate (discharge, in \( \text{m}^3/\text{s} \))
• \( C_d \): Discharge coefficient (typically 0.6–0.65, default 0.8)
• \( A \): Orifice area (\( A = \pi \times (d/2)^2 \), in \( \text{m}^2 \))
• \( g \): Gravitational acceleration (default 9.81 \( \text{m/s}^2 \))
• \( H \): Mean centerline head (height of fluid above the orifice center, in meters)

Use the form to input the orifice diameter, head, discharge coefficient, and gravitational acceleration to calculate the flow rate.

Using the Orifice Flow Calculator

This calculator estimates the flow rate of liquid through an orifice, commonly used in fluid mechanics for flow metering or restriction in pipes, tanks, and hydraulic systems.

Enter the orifice diameter, mean centerline head, discharge coefficient (optional, default 0.8), and gravitational acceleration (optional, default 9.81 m/s²). Choose units for diameter (mm, cm, m, in) and head (m, cm, mm, ft, in). The calculator provides the flow rate in multiple units (m³/s, L/min, ft³/min, gal/min).

Example: Calculate the flow rate for an orifice with a 40 mm diameter and a 10 m head, using a discharge coefficient of 0.6 and default gravity (9.81 m/s²).

1. Orifice Diameter: 40 mm
2. Mean Centerline Head: 10 m
3. Discharge Coefficient: 0.6
4. Gravitational Acceleration: 9.81 m/s²
5. Result: Flow Rate ≈ 0.01056 m³/s, 633.60 L/min, 22.38 ft³/min, 2,792.52 gal/min.

Use this tool for designing hydraulic systems, water tanks, or flow measurement in engineering applications, leveraging Bernoulli’s principle and the continuity equation.