U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Physical Measurement Laboratory / Sensor Science Division

Fluid Metrology Group

Projects/Programs

Displaying 1 - 10 of 10
acoustic resonator

Acoustic Techniques in Fluid Metrology

Ongoing
We use acoustic techniques in gases to measure the thermodynamic temperature of a gas in a spherical or cylindrical cavity, the optical absorption in gases and aerosols (in collaboration with NIST’s Chemical Sciences Division) the quantity of gas in a large vessel or tank, and gas flow into/from a
The NIST wind tunnel

Air Speed Metrology

Ongoing
NIST's wind tunnel has two interchangeable test sections. (See Fig. 1) The upper test section has a uniform cross section; the lower test section has a contracted zone in its center to achieve higher velocities. Upper test section: 2.1 m high × 1.5 m wide × 12 m long; speeds to: 45 m/s (100 mi/hour)
SLowFlowS diagrams

Flow Metering and Properties for Semiconductor Process Gases

Ongoing
A type of flow meter called a mass flow controller (MFC) is used to regulate gas flow in order to produce the desired structures during chip fabrication. As semiconductor manufacturing advances, the requirements on MFC performance are increasingly strict: any process variation can reduce device
two-capillary viscometer

Gas properties for flow metering

Ongoing
NIST has two on-line databases that include accurate gas viscosity values: SEMIPROP - NIST Standard Reference Database 134 - for selected semiconductor process gases NIST Chemistry WebBook - for heat transfer fluids, components of air, components of natural gas [Note: as of February 2014, the NIST
hydrogen gas dispensers test

Portable Field Test Standard for Evaluation of Hydrogen Gas Dispensers

Completed
This project provides a metrological tool and standards supporting the fair trade of hydrogen gas as a vehicle fuel of the future. Objective(s): The Fluid Metrology Group (FMG) and the Office of Weights and Measures (OWM) collaborated in designing, constructing, and testing a hydrogen gas dispenser
NIST researchers measuring a flow profile

Smoke Stack Flow Measurement

Completed
The Fluid Metrology Group is using its smoke stack simulator (See Fig. 1.) and field tests in operating smoke stacks to critically test conventional and improved ways of measuring the flow of stack gases. In the NIST stack simulator, the inlet cone and reference (upstream) section of the simulator
water flow standard

Temperature Sensitivity of Liquid Flow Meters

Completed
The Fluid Metrology Group is using NIST’s 15 kg/s water flow standard (Fig. 1) to test how coriolis meters are affected by liquid and environment temperatures. The water flow standard is a closed-loop, dynamic liquid flow calibration facility that is fully automated. For this work, calibrations were
Transient flow facility for vehicle refueling

Transient Flow Facility

Completed
Impact Provide metrological tools and standards supporting the fair trade of hydrogen gas as a vehicle fuel of the future. Objectives Design, construct, and utilize a facility that mimics retail hydrogen fueling station conditions to quantify uncertainties of flow measurement standards and
temperature distribution graphs

Understanding Flow Meters

Ongoing
Critical flow venturis (CFVs) are widely used for gas flows of 1 L/min or more, if a significant pressure drop is acceptable. Theoretical discharge coefficient ( Cd): A calculated value of the discharge coefficient allows 0.3% uncertainty from a CFV from a low uncertainty throat diameter measurement