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Search Publications by: Aaron Johnson (Fed)

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Displaying 26 - 50 of 53

Improved Nozzle Manifold for Gas Flow Calibrations

June 20, 2012
Author(s)
Aaron N. Johnson, Chunhui Li, John D. Wright, Gina M. Kline, Christopher J. Crowley
We developed a new nozzle manifold that reduced the uncertainty of flow calibrations from 0.09 % to as low as 0.074 % for flows of air up to 0.84 kg/s (43 000 L/min at reference conditions of 101.325 kPa and 293.15 K). The nozzle manifold also reduces the

Extended Lee model for the turbine meter & calibrations with surrogate fluids

May 1, 2012
Author(s)
Jodie G. Pope, John D. Wright, Aaron N. Johnson, Michael R. Moldover
We developed a physical model termed the “extended Lee model” for calibrating turbine meters to account for 1) fluid drag on the rotor, 2) bearing static drag and 3) bearing viscous drag. We tested the extended Lee model using a dual rotor, 2.5 cm diameter

Bilateral Comparison between NIST and PTB for Flows of High Pressure Natural Gas

April 6, 2012
Author(s)
Aaron N. Johnson, B Mickan, H. Toebben, Tom Kegel
In 2009 NIST developed a U.S. national flow standard to provide traceability for flow meters used for custody transfer of pipeline quality natural gas. NIST disseminates the SI unit of flow by calibrating a customer flow meter against a parallel array of

Comparison of Gas Velocity Measurements and CFD Predictions in the Exhaust Duct of a Stationary Source

July 13, 2011
Author(s)
Rodney A. Bryant, Olatunde B. Sanni, Elizabeth F. Moore, Robert P. Borthwick, Marco G. Fernandez, Iosif I. Shinder, Jiann C. Yang, Aaron N. Johnson
Two series of independent flow measurements were conducted for cross validation of flow velocity in the exhaust duct of the NIST Large Fire Laboratory. In the first series, two pressure measurement probe types, an S probe and a 3-D probe, were used to

Bilateral Comparison Confirms NIM’s and NIST’s Gas Flow Capabilities

October 15, 2010
Author(s)
Aaron N. Johnson, CHUNHUI LI
The bilateral comparison between NIM and NIST for gas flow was conducted from June 2008 to October 2009. Two critical flow venturis (CFVs) with nominal throat diameters of 10 mm and 20 mm, respectively, were selected as transfer standards. The CFVs were

Gas Flowmeter Calibrations With the 26 m 3 PVTt Standard

November 25, 2009
Author(s)
Aaron N. Johnson, John D. Wright
This document describes NIST s 26 m3 pressure, volume, temperature, and time (PVTt) primary flow standard. This standard is used to calibrate gas flow meters over a range extending from 200 standard L/min to 77,000 standard L/min where the reference

NIST Calibration Services for Liquid Volume

November 24, 2009
Author(s)
Vern E. Bean, Pedro I. Espina, John D. Wright, J F. Houser, Sherry D. Sheckels, Aaron N. Johnson
NIST provides calibration services for metal volume provers for liquid volumes from 4 L to 7600 L using gravimetric and volumetric methods. This document describes the procedures and methods of calculation used in the calibration service. The covered

Gas Flowmeter Calibrations With the Working Gas Flow Standard

November 23, 2009
Author(s)
John D. Wright, Jean-Phillipe Kayl, Aaron N. Johnson, Gina M. Kline
The Working Gas Flow Standard (WGFS) uses critical venturis, critical nozzles, or laminar flowmeters as working standards to calibrate customer flowmeters. The working standards are periodically calibrated with primary standards: the 34 L, 677 L, or 26 m3

The Calculation of Natural Gas Viscosity

August 14, 2009
Author(s)
Aaron N. Johnson, William Johansen
The calculation of natural gas viscosity has been implemented many different ways including the use of constants. Different methods of calculating natural gas viscosity may produce values with differences as large as 50%. Increasing natural gas prices

Natural Gas Flow Calibration Service

August 1, 2008
Author(s)
Aaron N. Johnson
This document describes NIST's high pressure natural gas flow calibration service (NGFCS). Flow calibrations are conducted offsite at the Colorado Experimental Engineering Station Incorporated (CEESI) in Garner, Iowa. A parallel array of nine turbine meter

Comparisons by PTB, NIST, and LNE-LADG in Air and Natural Gas With Critical Venturi Nozzles Agree Within 0.05 %

May 16, 2006
Author(s)
B Mickan, Roland H. Kraemer, D Dopheide, Hans-Jurgen Hotze, Heino-Michael Hinze, Aaron Johnson, John D. Wright, J-P Vallet
The PTB, NIST, and LNE-LADG conducted a comparison of gas flow measurement standards in air and natural gas in the pressure range from 0.9 to 42 bar. The artifacts used in the intercomparisons were four critical venturis with ISO standard toroidal shape

Relaxation Effects in Small Critical Nozzles

January 1, 2006
Author(s)
Aaron N. Johnson, C L. Merkle, Michael R. Moldover, John D. Wright
We computed the flow of four gases (He, N 2, CO 2, and SF 6) through a critical nozzle by augmenting traditional computational fluid dynamics (CFD) with a rate equation that accounts for τ relax, a species-dependent relaxation time that characterizes the

Uncertainty and Traceability for the CEESI Iowa Natural Gas Facility

September 1, 2004
Author(s)
Aaron N. Johnson, Tom Kegel
This paper presents an uncertainty analysis for the CEESI Iowa natural gas calibration facility. This facility calibrates flow meters up to flows of 10.7 actual m3/s, at nominal pressures of 174 kPa. Flow meters are calibrated by a set of nine turbine

Gas Flowmeter Calibrations with the 34 L and 677 L PVTt Standards

June 23, 2004
Author(s)
John D. Wright, Aaron N. Johnson, Michael R. Moldover, Gina M. Kline
This document provides a description of the 34 L and 677 L pressure, volume, temperature, and time (PVTt) primary gas flow standards operated by the National Institute of Standards and Technology (NIST) Fluid Flow Group. These facilities are used to

Volumetric Gas Flow Standard with Uncertainty of 0.02% to 0.05%

November 1, 2003
Author(s)
John D. Wright, Michael R. Moldover, Aaron N. Johnson, A Mizuno
A new pressure, volume, temperature, and time (PVTt) primary gas flow standard for calibrating flowmeters has an expanded uncertainty (k = 2) of between 0.02% and 0.05%. The standard diverts a steady flow into a collection tank of known volume during a

Design and Uncertainty Analysis for a PVTt Gas Flow Standard

February 1, 2003
Author(s)
John D. Wright, Aaron N. Johnson, Michael R. Moldover
A new pressure, volume, temperature, and time (PVTt) primary gas flow standard has been constructed at the National Institute of Standards and Technology with an expanded uncertainty of between 0.02 % and 0.05 % (k = 2). The standard covers a flow range of

Error Free Liquid Flow Diverters for Calibration Facilities (FEDSM2002-31085)

January 1, 2002
Author(s)
Tsyh Tyan Yeh, Aaron N. Johnson, Pedro I. Espina, N Yende
A design for diverter valves in gravimetric liquid flow calibration facilities is proposed. The concept makes use of repeated unidirectional motions of the diverter valve to reduce errors associated with asymmetry in the diverter valve motion and in the

Optimization of an Annular Jet Commercial Gas-Metal Atomizer

December 1, 2000
Author(s)
Stephen D. Ridder, Aaron N. Johnson, Pedro I. Espina, Frank S. Biancaniello, G J. DelCorso
The performance of a commercial gas-metal atomizer was studied using a number of previously published research techniques. initially the flow was visualized using schlieren photography to determine the location of important flow features (e.g., shock waves