This simulator models a Venturi flow meter — a shaped constriction that accelerates flow through a narrow throat and recovers pressure downstream through a diffuser — complete with a differential-pressure transmitter and a virtual U-tube manometer for inferring flow from the pressure differential. Adjust imposed flow, inlet/exit bore, inlet pressure, throat/inlet diameter ratio β, diffuser loss coefficient and the meter's calibration coefficient to see how the physical hydraulics and the metering instrumentation interact.
• A real-time 3D scene of the bolted upstream meter spool, the smooth converging section, the constant-diameter throat, the long pressure-recovery diffuser, the downstream recovered-pressure exit spool, a differential transmitter and impulse-tube manifold, and a virtual dense-liquid U-tube manometer, with home view, focus-selected-part, show-full-enclosure, exploded view, auto-rotate, expand and show/hide labels controls. • An Equipment laboratory tab with a labeled parts index (inlet, convergent section, throat, diffuser, exit, meter transmitter, manometer) and click-to-inspect component callouts. • Six experiment controls: imposed volume flow (0–8 L/s), inlet/exit bore (60–120 mm), inlet gauge pressure (5–180 kPa(g)), throat/inlet diameter ratio β (0.3–0.8), diffuser loss coefficient on a throat-velocity basis (0–0.8) and the flow-indicator calibration coefficient (0.9–1). • Playback controls: pause/resume, advance 0.1 s, advance 1 s, and four playback speeds (10× slow motion, real time, 10× faster, 1 minute per second), plus start/stop animation, toggle transmitter equalization and match-modeled-meter-coefficient actions. • A Curves & measurements tab with two live charts (station pressures and actual-vs-indicated flow), the governing meter equations (β and area ratio, convergent loss, differential pressure, true discharge coefficient, indicated flow, manometer relation) and snapshot measurement readouts. • An Experiments tab with four guided fixtures (nominal meter, wide throat, lossy diffuser, equalized transmitter) and a Model verification bench that runs independent deterministic checks against a fresh model without disturbing your live experiment, plus a timestamped event log and a copyable trial report. • A Learn & assess tab with guided lessons, a knowledge-check quiz with reset, and a written model-scope statement with a technical-background reference link.
Conservation of volume through a smaller throat area (a fraction β² of the inlet area) forces velocity to rise there, and by Bernoulli's principle that higher velocity is accompanied by lower static pressure at the throat — the inlet-to-throat pressure differential is what the transmitter measures and what the flow indicator converts back into an indicated flow rate using a calibration coefficient.
Downstream, the diffuser gradually decelerates the flow, converting velocity head back into static pressure — the exit pressure partially recovers from the throat's low point but ends up below the inlet pressure by the permanent meter loss, which includes both the small convergent loss and the diffuser's selected loss coefficient. Throat differential is therefore not the same thing as permanent head loss; the simulator's 'lossy diffuser' experiment isolates this by showing the differential stays fixed (since flow is imposed) while exit pressure recovery falls as diffuser loss increases.
The differential transmitter and manometer are diagnostic instruments layered on top of the physical hydraulics, and the simulator deliberately separates the two: the 'equalized transmitter' experiment shows that blocking the impulse lines drives the measured differential and indicated flow to zero even though the true physical flow keeps moving — a classic instrumentation fault that must be diagnosed on the instrument, not assumed to mean the process stopped.
This is a steady, one-dimensional, incompressible-water model with horizontal equal inlet/exit bores, teaching-parameter loss coefficients (not an ISO-calibrated meter or Reynolds-dependent discharge coefficient fit), and no impulse-line lag or dynamic manometer oscillation. Below 2.34 kPa absolute pressure, single-phase validity is flagged rather than silently assumed. Matching the meter's calibration coefficient in the simulator is a model exercise, not a real instrument calibration procedure.
No. The diffuser recovers some of the velocity head lost at the throat, converting it back into static pressure. Permanent head loss is the inlet pressure minus the recovered exit pressure at equal elevation and bore — it is smaller than, and physically distinct from, the raw inlet-to-throat differential the transmitter measures.
It reads zero, because both transmitter ports see the same pressure regardless of the real flow through the meter — the physical flow can continue unchanged even though the instrument reports no differential. This is a diagnostic fault the simulator deliberately models as a separate scenario.
Area ratio scales with β², so a smaller β (narrower throat relative to the inlet) produces a much larger velocity increase and pressure differential for the same flow, per Q = A·v and the meter's differential-pressure equation. The simulator's 'wide throat' experiment (β = 0.8) shows the opposite: velocity and differential pressure drop at the same actual flow.
No. The loss and discharge coefficients here are teaching parameters, not values derived from an ISO-standard calibration or Reynolds-number-dependent correlation, and the model excludes impulse-line lag and dynamic manometer effects. A real meter requires a validated calibration per the applicable flow-measurement standard.