Orifice Flow Calculator
Calculate flow rate through orifices using Torricelli's law and discharge coefficients
Calculate Orifice Flow
Diameter of the circular orifice opening
Area = π × (d/2)²
Typical values: 0.6-0.8 (Auto estimates based on Reynolds number)
Distance from water level to center of orifice
Standard Earth gravity: 9.81 m/s²
Flow Calculation Results
Flow Properties
Orifice Flow Equation: Q = Cd × A × √(2gH)
Theoretical Flow: 0.000000 m3/s
Based on: Torricelli's law and discharge coefficient correction
Flow Analysis
Example Calculation
Water Tank Orifice
Given:
• Orifice diameter: 50 mm
• Centerline head: 200 mm
• Discharge coefficient: 0.8
• Gravity: 9.81 m/s²
Calculation
• Area: A = π × (0.05/2)² = 0.001963 m²
• Q = 0.8 × 0.001963 × √(2×9.81×0.2)
• Q = 0.8 × 0.001963 × 1.98
• Q = 0.0031 m³/s = 3.1 L/s
Typical Discharge Coefficients
Applications
Flow Measurement
Orifice meters in pipelines
Tank Drainage
Water tank outlet design
Hydraulic Systems
Pressure control valves
Spray Nozzles
Irrigation and sprinkler systems
Pool Systems
Drain and overflow design
Process Control
Chemical and pharmaceutical industries
Understanding Orifice Flow
What is an Orifice?
An orifice is a circular opening (hole) in a plate or wall that allows fluid to flow through. It's commonly used to control flow rate, measure flow, or create pressure drops in fluid systems. The orifice creates a restriction that accelerates the fluid and causes a pressure drop.
Key Principles
- •Based on Torricelli's law (application of Bernoulli's principle)
- •Flow velocity depends on head (height difference)
- •Discharge coefficient accounts for real-world losses
- •Vena contracta effect reduces effective flow area
Key Equations
Orifice Flow Equation:
Q = Cd × A × √(2gH)
Orifice Area:
A = π × (d/2)²
Velocity:
V = Q / A
Reynolds Number:
Re = V × d / ν
Q: Flow rate (m³/s)
Cd: Discharge coefficient (0.6-0.98)
A: Orifice area (m²)
g: Gravitational acceleration (9.81 m/s²)
H: Head (pressure difference, m)
d: Orifice diameter (m)
ν: Kinematic viscosity (m²/s)
Factors Affecting Flow
Orifice Geometry
Diameter, edge condition (sharp vs. rounded), thickness
Head Pressure
Height difference or pressure differential across orifice
Fluid Properties
Density, viscosity, temperature affects discharge coefficient
Vena Contracta
Jet contraction downstream of orifice reduces effective area
Design Considerations
Cavitation
High velocities can cause vapor bubbles
Reynolds Number
Affects discharge coefficient selection
Accuracy
±2-5% with proper coefficient selection
Installation
Upstream/downstream pipe length requirements