Calculator Inputs
Plotly Graph
This graph compares ideal and actual nozzle velocity against pressure drop.
Example Data Table
| Inlet Pressure (kPa) | Outlet Pressure (kPa) | Density (kg/m³) | Diameter (mm) | Nozzles | Actual Velocity (m/s) | Flow Rate (L/s) | Jet Power (kW) |
|---|---|---|---|---|---|---|---|
| 500 | 120 | 998 | 28 | 2 | 25.9033 | 31.900 | 10.681 |
Formula Used
This model is best for incompressible or low-compressibility flow. For choked gas flow or highly compressible nozzles, use isentropic gas relations instead.
How to Use This Calculator
- Enter inlet and outlet pressures in kPa.
- Provide fluid density, viscosity, and inlet velocity.
- Set elevation change, loss coefficient, discharge coefficient, and efficiency.
- Enter nozzle diameter and number of nozzles.
- Click the calculate button to view results, export files, and inspect the graph.
Frequently Asked Questions
1. What does this calculator estimate?
It estimates nozzle exit velocity using pressure change, elevation, inlet velocity, losses, discharge coefficient, and efficiency. It also returns flow rate, Reynolds number, dynamic pressure, and jet power.
2. Which fluid units should I use?
Use kPa for pressure, kg/m³ for density, Pa·s for viscosity, mm for diameter, m for elevation, and m/s for velocity. Keeping units consistent prevents incorrect outputs.
3. Why are ideal and actual velocity different?
Ideal velocity ignores practical losses. Actual velocity includes discharge coefficient, efficiency, and loss coefficient, so it better reflects real nozzle behavior.
4. What does the loss coefficient represent?
The loss coefficient represents extra energy dissipation caused by fittings, surface effects, contraction, or internal flow disturbances. Higher loss values reduce the available exit speed.
5. Can I use this for gases?
You can use it only for low-compressibility cases. High-speed gas nozzles may choke, and those cases need compressible-flow equations instead of this simplified energy model.
6. Why is Reynolds number included?
Reynolds number helps you judge flow regime. It can indicate whether viscous effects may be minor or important inside the nozzle.
7. What happens if inlet pressure is lower than outlet pressure?
The page flags that condition as invalid for this setup. A lower inlet pressure would not produce the expected forward acceleration through the nozzle.
8. What do the CSV and PDF buttons export?
They export the current result summary shown on the page. The PDF also includes the plotted chart, which is useful for reporting or documentation.