Plant engineering calculator · Updated 17 September 2026
Steam Nozzle Flow Calculator — Choked Mass Flow & Critical Pressure
Calculate ideal-gas steam/nozzle choked mass flow, critical pressure ratio and throat velocity scale from upstream absolute pressure, temperature, throat area, Cd, k and gas constant.
Inputs
Live results
- Choked mass flow 0.13910032 kg/s
- Choked mass flow 500.76114 kg/h
- Critical pressure ratio 0.54572773
- Critical downstream pressure 5.4572773 bar abs
Formula
ṁ=Cd·A·P0·sqrt[k/(RT0)]·(2/(k+1))^((k+1)/(2(k−1))).
Worked example
A 100 mm² throat at 10 bar abs and 450 K gives a screening sonic mass flow.
Assumptions and limits
- Ideal-gas isentropic screening model; wet steam needs property-based methods.
- Use absolute pressure and Kelvin temperature.
FAQs
What does this Steam Nozzle Flow Calculator calculate?
Calculate ideal-gas steam/nozzle choked mass flow, critical pressure ratio and throat velocity scale from upstream absolute pressure, temperature, throat area, Cd, k and gas constant.
What should I verify before final design?
Verify measured operating data, fluid properties, equipment curves, safety margins and the applicable OEM or engineering standard.
Why are intermediate results shown?
They expose assumptions and make unit, load and operating-condition errors easier to catch.