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

Published

Author(s)

Aaron N. Johnson, John D. Wright, Shin-ichi Nakao, C L. Merkle, Michael R. Moldover

Abstract

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 ventrui flows. This phenomenon explains why certian gases - like carbon dioxide - exhibit calibration characteristics that differ significantly from other gases (e.g., N2, O2, Ar, He and H2). A mathmatical model is developed which predicts this behavior, and vibrational non-equilbrium effects are further substantiated by two independent experiments.
Citation
Flow Measurement and Instrumentation
Volume
11
Issue
No. 4

Keywords

coefficient, critical flow nozzles, venturi flows

Citation

Johnson, A. , Wright, J. , Nakao, S. , Merkle, C. and Moldover, M. (2000), The Effect of Vibrational Relaxation of the Discharge Coefficient of Critical Flow Venturis, Flow Measurement and Instrumentation, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=830656 (Accessed May 23, 2022)
Created December 1, 2000, Updated February 17, 2017