Sharp-edged Orifice Flow
Estimate orifice discharge Q from coefficient Cd, dia. D and head H.
Inputs
Formula
Q = Cd·A·√(2gH), A=πD²/4, g=9.81
Orifices are used for metering and throttling.
Fundamentals
Estimate orifice discharge Q from coefficient Cd, dia. D and head H.
This tool computes Sharp-edged Orifice Flow from the formula: Q = Cd·A·√(2gH), A=πD²/4, g=9.81
History
Fluid mechanics and heat transfer were established in the 18th–19th centuries with steam engines and thermodynamics.
Engineering applications
Used for piping, heat-exchange and hydraulic system estimates.
Glossary
| Discharge Cd | Input parameter |
| Orifice dia. D | Input parameter |
| Head H | Input parameter |
| Area A | Output result |
| Flow Q | Output result |
How to use
- Fill in Discharge Cd, Orifice dia. D, Head H in the Inputs section (watch the unit on each field).
- Click Calculate; the tool evaluates the formula shown above.
- Read Area A, Flow Q in the results area.
Formula · Worked Example · Knowledge
Formula
核心计算关系：Q = Cd·A·√(2gH), A=πD²/4, g=9.81
输入变量：
- Discharge Cd
Cd - Orifice dia. D
D— mm - Head H
H— m
输出结果：
- Area A
A— mm² - Flow Q
Q— L/s
假设/适用：Flow formulas assume steady, incompressible, continuous flow; correct for compressible/high-speed.
Worked Example
根据公式 Q = Cd·A·√(2gH), A=πD²/4, g=9.81，取 Discharge Cd = 0.62；Orifice dia. D = 20 mm；Head H = 3 m。
代入计算得：Area A = 314.2 mm²；Flow Q = 1.494 L/s。
Key Points
- Flow formulas assume steady, incompressible, continuous flow; correct for compressible/high-speed.
- Reynolds Re sets laminar/turbulent; friction f depends on regime & roughness.
- Energy eqn includes elevation, pressure and velocity heads; keep units as length.
Parameters
Inputs
| Parameter | Symbol | Unit | Default |
|---|---|---|---|
| Discharge Cd | Cd | 0.62 | |
| Orifice dia. D (mm) | D | mm | 20 |
| Head H (m) | H | m | 3 |
Outputs
| Result | Symbol | Unit |
|---|---|---|
| Area A | A | mm² |
| Flow Q | Q | L/s |
Applications
- Pipe flow rate and pressure drop
- Hydraulic cylinder force/speed design
- Flow-meter selection and calibration
FAQ
What formula does this tool use?
This tool computes per ISO / AGMA / ASME standard formulas: Q = Cd·A·√(2gH), A=πD²/4, g=9.81
How accurate are the results?
Results match input precision, based on SI units and common engineering approximations; for critical duty re-check with a safety factor.
Where is it used?
Pipe flow rate and pressure drop