U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Physical Measurement Laboratory /Sensor Science Division

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

Projects and Programs

shaded quasi sphere

Atomic Standard for Pressure

NIST scientists are developing a highly accurate primary standard for pressure in the range 2 MPa to 7 MPa based on fundamental physical properties of helium.
Diagram of NIST's Smoke Stack Simulator test bed

Smoke Stack Simulator

Today, inconsistencies between measured CO2 emissions and emissions calculated from coal consumption are on the order of 10% to 20%. The objective of this
Transient flow facility for vehicle refueling

Transient Flow Facility

Today, demonstration vehicles are refueled with hydrogen from dispensers within 3 to 5 minutes using sequential gas releases from a bank of pressurized
The NIST wind tunnel

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

Publications

REFRACTIVE-INDEX GAS THERMOMETRY

Author(s)
Patrick Rourke, Christof Gaiser, Roberto M. Gavioso, Michael R. Moldover, Laurent Pitre, Robin Underwood
The principles and techniques of primary refractive-index gas thermometry (RIGT) are reviewed. Absolute primary RIGT using microwave measurements of helium

Tools and Instruments

transient gas flow 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
cryogenic flow loop instrument

Cryogenic Flow Loop

NIST developed a cryogenic flow loop; it is the only internationally-recognized facility for calibrating flow meters operating with liquid nitrogen. (After
gas flow standards instrument

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

Awards

Products and Services

Related Links

Contacts

Group Leader

Office Manager