Physics calculator

ISO 5167 Nozzle Calculator

Q: Is this a venturi meter?

No. A classical venturi with a given C_d (default 0.98) is /calc/physics/venturi. Sending C_d here is MIXED_INPUT_ENCODING. At β=0.5 and Re_D=10⁶ this page reports C≈0.97656, not 0.98.

Q: Is this an orifice meter?

No. A given C_d plate is /calc/physics/orifice-discharge (default C_d=0.61). ISO 5167-2 Reader–Harris/Gallagher C from β and Re_D is /calc/physics/iso-orifice. Sending d and D here is MIXED_INPUT_ENCODING.

Q: Is this Q = A·v?

No. Volumetric flow from a given area and velocity is /calc/physics/flow-rate. Sending A or v is MIXED_INPUT_ENCODING.

Q: Can I invert C_d from Q?

No. C is computed from β and Re_D. Venturi invert Cd is /calc/physics/venturi. mode=Cd is INVALID_MODE.

Q: Where does this run?

Locally in the browser by default. REST and MCP call the same fluid-engine isoNozzle wrapper.

Compute ISO 5167-3 ISA 1932 nozzle discharge with C from β and Re_D, not a given C_d. Runs locally. Not a venturi wrap with C_d=0.98, not orifice C_d=0.61, not Q=Av, and not Darcy.

Instant result

Result

—

Enter values to calculate.

Inputs—

Mode—

Formula—

Trust summary Engine tested · Source checked · 5/5 tests · Production surface contract 1/1 · v1.0.0

Input interpretation: Enter values to calculate.
Result: —
Model: ISO 5167-3 ISA 1932 incompressible nozzle discharge from D1, D2 or β, Re_D, and Δp. Invert Δp. Report C from β and Re_D.
Scope: ISO 5167-3 ISA 1932 nozzle: Q = C E A2 √(2Δp/ρ); C from β and Re_D; incompressible ε=1; C is reported, not an input
Verification: Engine tested · 5/5 tests · Production surface contract 1/1 · Source checked · v1.0.0
Named expert review: Optional · Not performed
Sources: ISO 80000-4 — Mechanics — Length, speed, pressure
ISO 5167-3 — Measurement of fluid flow by means of pressure differential devices — Nozzles and Venturi nozzles — ISA 1932 nozzle discharge coefficient
Sources
Evidence: 5 property · Production surface contract 1/1 · Artifact integrity PASS
Production: Embedded snapshot: STALE · Last attested schema matched 1.0.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status STALE (1 capability; 163 remain CURRENT) @ 2026-09-17T23:16:16.380Z
Semantic contract: PASS

Formulas

Core equations used by this calculator.

DischargeQ = C E A2 √(2Δp / ρ)

Approachβ = D2/D1 · E = 1/√(1 − β⁴)

ISA 1932 CC = 0.9900 − 0.2262 β^4.1 − (0.00175 β² − 0.0033 β^4.15)(10^6/Re_D)^1.15

iSI. Incompressible ε=1. C is reported from β and Re_D; do not send C_d. Do not send query v — that is calculation_version.

How to use

Enter D1 and D2

Inlet D1 ≥ 50 mm and throat D2. REST may send D1+beta instead of D2. This is not an orifice d+D pair.

Enter Re_D

Pipe Reynolds number on D1. Do not send ρ, μ, and v to wrap the Reynolds page.

Enter Δp and ρ

Inlet-to-throat differential pressure. Invert on the Δp tab. Read C on the C tab without Δp.

Example calculations

Common configurations with formula and result.

β=0.5, Re_D=10⁶, 10 kPa

D1=0.1 m, D2=0.05 m, Δp=10 kPa, ρ=1000 kg/m³

C from ISA 1932, Q=C E A2 √(2Δp/ρ)

C≈0.97656 · Q≈0.008856 m³/s

Same β via D1+beta

D1=0.1 m, beta=0.5

D2=β D1

same C

ISO 5167 Nozzle calculator specification

Version 1.0.0 · Engine tested

Calculation status

Engine tested 5/5 tests · Production surface contract 1/1
Named expert review Not performed
Calculation version 1.0.0

Review policy · Evidence

Definition: ISO 5167-3 ISA 1932 nozzle. Incompressible Q = C E A2 √(2Δp/ρ) with E=1/√(1−β⁴). C is computed from β and Re_D, not supplied. β∈[0.30,0.80], Re_D∈[7×10⁴,10⁷], D≥50 mm. Not a venturi tube with given C_d=0.98, not a sharp-edged orifice with C_d=0.61.
What it calculates: ISO 5167-3 ISA 1932 incompressible nozzle discharge from D1, D2 or β, Re_D, and Δp. Invert Δp. Report C from β and Re_D.
Inputs: mode?
D1
D2|beta
Re_D
dP?
rho?
Q?
Outputs: Q?
D1
D2
beta
E
A1
A2
C
Cd
Re_D
v1?
v2?
rho?
dP?
mode
model
Formula: Q = C E A2 √(2Δp/ρ); C = 0.9900 − 0.2262 β^4.1 − (0.00175 β² − 0.0033 β^4.15)(10^6/Re_D)^1.15
Assumptions: ISO 5167-3 ISA 1932 nozzle: Q = C E A2 √(2Δp/ρ); C from β and Re_D; incompressible ε=1; C is reported, not an input
C = 0.9900 − 0.2262 β^4.1 − (0.00175 β² − 0.0033 β^4.15)(10^6/Re_D)^1.15; β∈[0.30,0.80]; Re_D∈[7e4,1e7]; D≥50 mm
Not a venturi wrap with given C_d=0.98, not orifice C_d=0.61, not Q=Av, not Darcy f, not compressible ε
Units: SI; D1, D2 in m; Q in m³/s; Δp in Pa; ρ in kg/m³; Re_D dimensionless
Boundary conditions: missing D1, D2/beta, Re_D, Δp, Q, or ρ when required → MISSING_REQUIRED_INPUT
D1 < 50 mm, β outside [0.30,0.80], or Re_D outside [7e4,1e7] → VALUE_OUT_OF_RANGE
C_d given, orifice d+D, A or v, Darcy f, μ, tank H, Cv/Kv, K, ε, kind → MIXED_INPUT_ENCODING
mode=Cd or unknown mode → INVALID_MODE
Example: D1=0.1 D2=0.05 Re_D=1e6 dP=10000 rho=1000 → C≈0.97656 Q≈0.008856
Validation cases: 3 published on this page · 5/5 tests · Production surface contract 1/1 · View evidence
D1=0.1 D2=0.05 Re_D=1e6 dP=10000 rho=1000 → C≈0.97656 Q≈0.008856
D1=0.1 D2=0.05 Re_D=1e6 Cd=0.98 → MIXED_INPUT_ENCODING
mode=Cd D1=0.1 D2=0.05 Re_D=1e6 → INVALID_MODE
Sources: ISO 80000-4 — Mechanics — Length, speed, pressure
Supports: D is a length; Q is a volume flow; Δp is a pressure
ISO 5167-3 — Measurement of fluid flow by means of pressure differential devices — Nozzles and Venturi nozzles — ISA 1932 nozzle discharge coefficient
Supports: C from β and Re_D. Not a venturi with given C_d, not an orifice plate
Calculation version: 1.0.0

Background

Interpretation and common distinctions.

Compute ISO 5167-3 ISA 1932 nozzle discharge from β, Re_D, and Δp. C is computed, not supplied.

Supported and not supported

Supported — Q from D1, D2 or β, Re_D, and Δp · invert Δp · C from β and Re_D · API physics.fluid.iso_nozzle

Not supported — given venturi C_d=0.98, orifice C_d=0.61, Q=Av, Darcy f, compressible ε, long-radius nozzle, Venturi nozzle

Agent / API notes

Capability id: physics.fluid.iso_nozzle · tool id: iso-nozzle · pin 1.0.0.

{ "D1": 0.1, "D2": 0.05, "Re_D": 1000000, "dP": 10000, "rho": 1000 }

Modes: flow (default), pressure, coefficient. Errors: MISSING_REQUIRED_INPUT, INVALID_NUMBER, VALUE_MUST_BE_POSITIVE, VALUE_OUT_OF_RANGE, MIXED_INPUT_ENCODING, INVALID_MODE.

Calculator URL stays /calc/physics/iso-nozzle. There is no /calc/fluid.

Other calculators in this family: Venturi meter, Orifice discharge, ISO 5167 orifice, Flow rate, Concentric reducer .

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Frequently asked questions

Key distinctions behind the calculation.

Is this a venturi meter?