Estimate nozzle pressure drop, throat pressure, velocity changes, and losses. Export clean reports, inspect graphs, and compare flow conditions quickly.
This calculator combines continuity, Bernoulli’s equation, and a minor loss model. It estimates pressure drop across a nozzle from velocity rise, nozzle losses, and elevation effects.
Flow stays constant through the nozzle.
Q = A × V
So, V₁ = Q / A₁ and V₂ = Q / A₂.
A discharge coefficient adjusts the ideal throat velocity.
V₂,effective = V₂ / Cd
The total pressure drop combines acceleration, losses, and elevation change.
ΔPtotal = 0.5ρ(V₂² - V₁²) + K(0.5ρV₂²) + ρgz
P₂ = P₁ - ΔPtotal
hL = ΔPtotal / (ρg)
The calculator also estimates flow regime at inlet and throat.
Re = ρVD / μ
A nozzle converts pressure energy into kinetic energy. When the passage narrows, velocity rises. That rise usually lowers static pressure. Real nozzles also add internal losses. The final pressure drop is therefore larger than the ideal Bernoulli estimate.
The throat area controls the velocity increase. A smaller throat creates a stronger acceleration. That stronger acceleration raises the dynamic pressure term. As a result, the pressure drop often becomes much larger as the throat diameter decreases.
The discharge coefficient corrects ideal flow behavior. Surface roughness, separation, vena contracta effects, and geometry imperfections all affect the actual stream. A lower coefficient means stronger deviation from ideal motion and usually a larger practical pressure reduction.
The minor loss coefficient captures energy losses not explained by acceleration alone. It includes internal friction, local turbulence, and geometric disturbance. This term is useful when a design has contraction effects, imperfect transitions, or additional fittings around the nozzle.
Viscosity affects boundary layer growth and energy dissipation. Reynolds number helps describe whether the flow is laminar or turbulent. Most engineering nozzles operate in turbulent conditions, but the Reynolds estimate still helps you judge whether assumptions remain realistic.
If the nozzle exit is higher than the inlet, gravity adds another pressure demand. If the exit is lower, gravity reduces some pressure loss. Including elevation makes the calculation more useful for vertical piping, injectors, and process lines.
It estimates nozzle pressure drop, throat pressure, inlet and throat velocities, Reynolds numbers, and total head loss using continuity, Bernoulli, and loss terms.
A nozzle contracts the flow path. If the throat is not smaller, the model no longer represents a real converging nozzle pressure drop case.
K represents local losses from contraction, turbulence, geometry effects, and internal disturbances. Larger K values produce a larger total pressure drop.
It adjusts ideal throat velocity to better reflect real flow behavior. Lower values indicate stronger deviation from ideal nozzle performance.
You can for rough incompressible-style estimates. For large gas pressure changes, compressibility effects become important and a dedicated compressible nozzle model is better.
They help describe the flow regime. This gives added context when checking whether the chosen assumptions and coefficients look physically reasonable.
Large flow rate, small throat diameter, high losses, or high elevation rise can strongly reduce pressure. Review your units and assumptions if values seem unrealistic.
Use SI units throughout: pascals, meters, kilograms per cubic meter, cubic meters per second, pascal-seconds, and meters per second squared.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.