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Search Publications by: Aaron Johnson (Fed)

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Displaying 51 - 60 of 60

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 Wright, Aaron Johnson, Michael Moldover, Gina 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

The Effect of Vibrational Relaxation of the Discharge Coefficient of Critical Flow Venturis

December 1, 2000
Author(s)
Aaron N. Johnson, John D. Wright, Shin-ichi Nakao, C L. Merkle, Michael R. Moldover
This paper identifies a new mechanism that can affect the discharge coefficient of critical nozzle flows. Specifically, vibrational relaxation effects are demonstrated to significantly influence the discharge coefficient of selected gases in critical

Uncertainty in Primary Gas Flow Standards Due to Flow Work Phenomena

June 1, 2000
Author(s)
John D. Wright, Aaron N. Johnson
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

Numerical Characterization Of The Discharge Coefficient In Critical Nozzles

July 1, 1998
Author(s)
Aaron N. Johnson, Pedro I. Espina, John D. Wright, G E. Mattingly, C L. Merkle
The discharge coefficient in critical nozzles flowing N 2, Ar, CO 2, and H 2 in the Reynolds Number range (2,000 to 22,000) is studied computationally to assess the capability of Computational Fluid Dynamics (CFD) in assisting experimental calibration. A
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