KEVOS® MAKEOS · Hydraulics
Jet Impact Force Check (Nozzle Flow and Velocity, Reaction, Force on a Plate)
For a water jet from a nozzle at this pressure, how much flow and speed does it have, what reaction does the operator or mounting feel, and what force does it put on a plate it hits?
Forces from a liquid jet: the flow and jet velocity through the nozzle from its size, discharge coefficient and pressure (as the orifice flow tool), the reaction force on the nozzle, and the force on a flat plate struck by the jet at an angle and possibly moving away from it, against the largest reaction force a hand-held nozzle or mounting should take.
Open the calculatorRuns in your browser. No account needed.
How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Nozzle orifice diameter | mm | Diameter of the nozzle orifice. |
| Discharge coefficient | Discharge coefficient of the nozzle (about 0.95 for a smooth nozzle, 0.6 for a sharp orifice). | |
| Pressure at the nozzle | bar | Pressure just upstream of the nozzle. |
| Liquid density | kg/m³ | Density of the liquid. |
| Target | ||
| Angle between the jet and the plate | ° | Angle between the jet and the plate surface (90 = jet square to the plate). |
| Plate speed away from the jet | m/s | Speed at which the plate moves away along the jet (0 for a fixed target). |
| Largest reaction force accepted | N | Largest kick-back force for a hand-held nozzle (from your safety guidance) or rating of the mounting. |
Method and formulas
- Flow Q = C_d A √(2Δp ÷ ρ); jet velocity = √(2Δp ÷ ρ) (as the orifice flow tool).
- Nozzle reaction = ρ Q v.
- Force normal to a plate = ρ Q (v − u)² ÷ v × sin β.
- Example: 141.57 L/min at 31.623 m/s; 74.613 N reaction and 74.613 N on the plate.
Limitations
- Single plate; a series of vanes or a bucket that turns the jet back takes up to twice the force.
- Jet treated as coherent up to the plate; long throws break up and lose force.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check the kick-back of a hand-held cleaning lance
- Find the force of a jet on a target or gate
- Size the mounting of a fixed spray nozzle
Who it is for
- Process engineers
- Safety advisers
- Maintenance engineers
What you get
- Flow and jet velocity
- Nozzle reaction
- Force on the plate
Interpreting the result
- Reaction force grows in proportion to pressure for a fixed nozzle: doubling the pressure doubles the kick.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 3024–3027, 352–368. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Jet Impact Force Check (Nozzle Flow and Velocity, Reaction, Force on a Plate) calculator
