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Choked Flow / Critical Pressure Ratio Checker

CHOKED FLOW · IEC 60534 / ISA

Choked Flow & Critical Pressure Ratio Checker

Check whether flow through a valve will choke at your operating conditions. Enter inlet and outlet pressures for gas or steam, or inlet pressure and fluid vapour pressure for liquids, and see how your duty point compares with the critical limit.

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Pressure Ratio Position

P2/P1 = 0 (full choke)1.0 (no flow drop)
Choked Approaching critical Sub-critical (OK)

Method

Engineering note: Critical pressure ratios shown are typical guidance values (gas ˜ 0.5, saturated steam ˜ 0.58). The exact value depends on the gas specific-heat ratio (k) and the valve’s pressure-recovery factor (F? / x?) from the manufacturer’s data. Use full IEC 60534 sizing for final selection.
Liquids: Liquids do not choke on sound — they cavitate or flash when local pressure falls below the fluid’s vapour pressure. This tool gives a first-pass cavitation index; confirm against the valve’s F? and incipient-cavitation data.

Built by Actuation Valve · Choked flow & critical pressure ratio · Gas, steam & liquid