Restriction Orifice Sizing

Single & multi-stage square-edged restriction orifices · gas choke + liquid cavitation checks · orifice guide · methodology.

Pipe ID, D

Mass flow, qm

Inlet P₁ (abs)

Outlet P₂ (abs)

Thickness ratio t/d

Density ρ₁

Viscosity μ

Isentropic exp. κ

Bore, d

44.174 mm

regime choked

CAUTION

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