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Publication Citation: Performance of Critical Flow Venturis under Transient Conditions

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Author(s): John D. Wright;
Title: Performance of Critical Flow Venturis under Transient Conditions
Published: April 13, 2010
Abstract: Critical flow venturis (CFVs) can be used to measure flow under transient pressure and flow conditions with uncertainties of 0.13 % or less (95 % confidence level). Blow-down tests transferred 630 g of nitrogen during a 100 s interval from an unregulated cylinder (initially at 10 MPa) through a heat exchanger and a CFV into a known collection volume. Fast pressure and temperature sensors were used to calculate the CFV flow. The integrated CFV mass flows,  , averaged 0.04 % smaller than the mass V of the collected gas. The heat exchanger was essential to the excellent agreement; without it, the percentage difference between  and V was 0.38 %. We conclude that even under transient conditions, a properly instrumented CFV can be used as a reference flowmeter to evaluate other flowmeter types or to test gaseous fuel dispensers in the field.
Citation: Measurement Science & Technology
Keywords: blow-down test, critical flow venture, critical nozzle, fuel dispenser, transient flow
Research Areas: Process Metrologies, Metrology, Flow