UNCERTAINTY IN PRIMARY GAS FLOW STANDARDS DUE TO FLOW WORK PHENOMENA

John D. Wright, Aaron N. Johnson

Abstract

Static gravimetric and static volumetric gas flow standards are both affected by uncertainty components related to the measurement of the change of mass of gas within the inventory volume. In the process of diverting gas into the collection vessel, rapid pressure and temperature changes occur in the inventory volume. A low uncertainty gas flow standard requires thorough understanding of these transients so that appropriate instrumentation, system design, and operating procedures may be developed. A thermodynamic model for the flow work phenomena is presented and compared to experimental measurements and strategies for minimizing their effects on flow uncertainty are discussed.

Keywords

primary gas flow standard, flow work, inventory volume, uncertainty, gas flow calibration, diverter valves

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IMEKO-TC9-2000-067.pdf

DOI

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IMEKO TC

TC9 - Flow Measurement

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