Restriction orifice sizing calculator
Size single- and multi-stage restriction orifices for pressure reduction. The calculator picks the discharge coefficient by geometry (ISO 5167 Reader–Harris/Gallagher for thin plates, Miller 1996 for thick), checks gas choking against the critical pressure ratio and liquid cavitation against the cavitation index, and stages a large drop at equal pressure ratio with per-stage verification and a minimum-stage count. Clause-cited, validated, browser-based and offline-capable.
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Bore, d
44.174 mm
regime choked
Choked service: P2/P1=0.1 ≤ rc=0.528. Sized on the critical-flow equation (flow independent of P2). Verify downstream conditions.Thick square-edged RO (t/d=2): Cd=0.839 from Miller's Handbook (1996) — non-ISO, stated uncertainty ~±2–5%.
restriction-orifice · miller-handbook:1996 — qm→Critical-flow (compressible) · C→Miller, Flow Measurement Engineering Handbook
Keep going
- Full restriction orifice calculator — datasheet, staging table and deliverable-grade PDF report.
- Orifice plate sizing guide — choking, cavitation and why you stage a large pressure drop.
- Metering orifice (ISO 5167) · methodology & V&V — for flow-measurement (not pressure-reducing) plates.