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Engineering Calculators
Ejector / Eductor Calculators
Steam and gas jet ejector nozzle, mixing, shock and diffuser calculations; liquid eductor flow ratio, head ratio, sizing and cavitation checks; staging, pump-down and equivalent-air screening. Selectable units and separate calculation history are included.
Clickable ejector / eductor workflow
Ejector and Eductor Design Flow
Follow the sequence from duty definition, through the fluid-type decision, to nozzle, mixing, diffuser, staging and vendor review. Each button opens the matching calculator.
Design inputCalculationDecision gateFinal closeout
Engineering boundary: preliminary sizing only. Final ejector selection requires vendor performance curves, HEI / ASME PTC 24 methods, project specifications and responsible-engineer approval.
Standards and engineering limitations
- HEI Standards for Steam Jet Vacuum Systems: ejector performance, air-equivalent correction, system arrangement and testing.
- ASME PTC 24: performance test procedure for ejectors.
- Gas equations use ideal-gas, one-dimensional isentropic flow with a single average k and MW. Wet steam, real-gas effects and mixed-property streams need an approved property package.
- The liquid eductor model is a one-dimensional momentum balance with loss coefficients (Kn, Kth, Kdi). Defaults are typical values; use manufacturer data where available.
- The pressure-prediction calculators (Pd from P0, P0 from Pd) assume mixing at the suction pressure Ps with a single average k and MW; results are screening values and do not replace vendor performance curves.
- Critical back pressure, off-design (turndown, variable motive pressure), nozzle erosion, noise, NPSH and condenser sizing are not covered here.
Important: Results are preliminary. Use absolute pressure and absolute temperature. Final ejector or eductor selection shall use vendor data, approved fluid properties and project specifications.