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Fluid Metrology Group

The Group develops models, standards, reference data, and novel calibration techniques for metering liquid and gas flows, airspeed, liquid density, and volume. We measure micro-flows (e.g., pharmaceuticals) and mega-flows (e.g., natural gas in major pipelines, pollutants from power plants).

The Group has encouraged the accurate calculation of the thermophysical properties of helium and argon from quantum mechanics as well as the use of the calculated properties as standards to calibrate instruments that measure flow, viscosity, thermal conductivity, dielectric constant, speed of sound, and the nist-equation of state.

News and Updates

Better Flowmeters with the Big Blue Ball

Last year, upwards of 25 trillion cubic feet of natural gas were delivered to customers in the United States, and when it changed hands, nearly every cubic foot

Projects and Programs

Air Speed Metrology

NIST's versatile wind tunnel is used to calibrate customers' air speed sensors and to conduct research on the design of novel anemometers, the responses of

Gas properties for flow metering

Flow meters that rely on measuring the pressure drop across a laminar flow element can be accurately calibrated using a benign surrogate gas (such as helium or

Understanding Flow Meters

Accurate flow measurements are needed for test fluids, temperatures, pressures, flows, and installation conditions that differ from those used during NIST's

Publications

Faster, More Accurate, Stack-Flow Measurements

Author(s)
Aaron N. Johnson, Iosif I. Shinder, Bernard J. Filla, Joey T. Boyd, Rodney A. Bryant, Michael R. Moldover, Thomaa D. Martz, Matthew Gentry
Exhaust flows from coal-fired electricity-generating-plants are determined by measuring the flue gas velocity at prescribed points in the stack cross section

Reproducibility of Liquid Micro-Flow Measurements

Author(s)
John D. Wright, James W. Schmidt
New applications in biology, medicine, and manufacturing require reliable measurements of liquid flows smaller than 100 υL/min. NIST addressed this requirement

Tools and Instruments

Transient Gas Flow Facility

A compressor is used to pressurize up to twenty-five 40 L gas cylinders to 35 MPa. The cylinders can then be used as a source of rapidly changing gas flow by

Gas Flow Standards

NIST uses pressure, volume, temperature, and time (PVTt) standards to calibrate gas flow meters. PVTt flow standards generate selected, steady gas flows through

Wind Tunnel

NIST’s wind tunnel can produce air speeds between 0.15 m/s and 40 m/s. The air speed reference is a Laser Doppler Anemometer (LDA) with an uncertainty of 2.5 %

Awards

Contacts

Group Leader

Office Manager