Flow Rate Through An Orifice Formula

Orifice Flow Equation:

\[ Q = C_d \times A \times \sqrt{2 \times g \times H} \]

Discharge Coefficient (C_d):

unitless

Orifice Area (A):

m²

Gravity (g):

m/s²

Head Difference (H):

Volumetric Flow Rate (Q):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Orifice Flow Equation?

The orifice flow equation calculates the volumetric flow rate of fluid through an orifice plate. It is based on Bernoulli's principle and accounts for energy losses through the discharge coefficient.

2. How Does the Calculator Work?

The calculator uses the orifice flow equation:

\[ Q = C_d \times A \times \sqrt{2 \times g \times H} \]

Where:

\( Q \) — Volumetric flow rate (m³/s)
\( C_d \) — Discharge coefficient (unitless)
\( A \) — Orifice area (m²)
\( g \) — Gravitational acceleration (m/s²)
\( H \) — Head difference across orifice (m)

Explanation: The equation calculates flow rate based on the pressure difference (head) across the orifice, the orifice geometry, and fluid properties.

3. Importance of Flow Rate Calculation

Details: Accurate flow rate calculation through orifices is essential for fluid system design, flow measurement, pump sizing, and process control in various engineering applications.

4. Using the Calculator

Tips: Enter discharge coefficient (typically 0.6-0.8 for sharp-edged orifices), orifice area in square meters, gravitational acceleration (9.81 m/s² on Earth), and head difference in meters. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical discharge coefficient value?
A: For sharp-edged circular orifices, C_d is typically 0.60-0.65. The value depends on orifice geometry and Reynolds number.

Q2: Can this equation be used for any fluid?
A: The equation works for incompressible fluids. For gases or compressible fluids, additional compressibility factors are needed.

Q3: What is the head difference (H)?
A: Head difference is the height difference of the fluid column that would produce the same pressure difference across the orifice.

Q4: Are there limitations to this equation?
A: The equation assumes steady, incompressible flow and may need corrections for viscosity effects, turbulence, and orifice edge conditions.

Q5: How accurate is this calculation?
A: Accuracy depends on proper C_d selection and measurement precision. Laboratory conditions can achieve ±2% accuracy, while field applications may have ±5% uncertainty.