State-of-the art dimensional metrology was used to measure the throat diameter and throat curvature of nine critical flow venturis (CFVs) with nominal throat diameters ranging from 5mmto25mm. The throat curvature was used in calculating the theoretical discharge coefficients, while the throat diameter was used in computing the experimental discharge coefficients. The nine CFVs were calibrated in dry air using two NIST primary flow standards with expanded uncertainties of 0.05% and 0.09%, respectively. The calibration data span a Reynolds number range from 7.2×104 to 2.5×106, including laminar, transition, and turbulent flow regimes. By correcting for both the throat diameter and curvature, the agreement between predicted and measured discharge coefficients was less than 0.17% in the turbulent regime and less than 0.07% in the laminar regime.

1.
Wright
,
J. D.
, 1998, “
The Long Term Calibration Stability of Critical Flow Nozzles and Laminar Flowmeters
,”
Proceedings of the 1998 NCSL Workshop and Symposium
,
Albuquerque, NM
,
NCSL
, pp.
443
462
.
2.
ISO 9300
: (E), 1990, “
Measurement of Gas Flow by Means of Critical Flow Venturi Nozzles
,” Geneva, Switzerland.
3.
Ishibashi
,
M.
,
Takamoto
,
M.
,
Watanabe
,
N.
,
Nakao
,
Y.
, and
Yokomizo
,
T.
, 1994, “
Precise Calibration of Critical Nozzles of Various Shapes at the Reynolds Number of 0.8–2.5×105
,”
Proceedings of Flow Measurement
,
Glasgow, UK
.
4.
Ishibashi
,
M.
,
Morioka
,
T.
, and
Arnberg
,
B. T.
, 2005, “
Effect of Inlet Curvature on the Discharge Coefficients of Toroidal-Throat Critical-Flow Venturi Nozzles (Keynote Paper)
,”
ASME Summer Meeting and Exhibition
,
Houston, TX
, ASME Paper No. FEDSM2005-77470.
5.
Ishibashi
,
M.
, 2003, “
Fluid Dynamics in Critical Nozzles Revealed by Measurements (Keynote Paper)
,”
Fourth ASME/JSME Joint Fluids Engineering Conference
,
Honolulu, HI
, ASME Paper No. FEDSM2005-45592.
6.
Ishibashi
,
M.
, 2002, “
Super-Fine Structure in the Critical Flow-Rate of Critical Flow Venturi Nozzles
,”
Joint US-European Fluids Engineering Conference
,
Montreal, Canada
, ASME Paper No. FEDSM2002-31079.
7.
Wright
,
J. D.
,
Johnson
,
A. N.
, and
Moldover
,
M. M.
, 2003, “
Design and Uncertainty Analysis for a PVTt Gas Flow Standard
,”
J. Res. Natl. Inst. Stand. Technol.
1044-677X,
108
, pp.
21
47
.
8.
Wright
,
J. D.
,
Moldover
,
M. R.
,
Johnson
,
A. N.
, and
Mizuno
,
A.
, 2003, “
Volumetric Gas Flow Standard With Uncertainty of 0.02% to 0.05%
,”
ASME J. Fluids Eng.
0098-2202,
125
(
6
), pp.
1058
1066
.
9.
Johnson
,
A. N.
, and
Wright
,
J. D.
, 2006, “
Gas Flowmeter Calibrations With the 26m3 PVTt Standard
,”
Journal of Research of the National Institute of Standards and Technology, NIST Special Publication 250-1046
.
10.
Johnson
,
A. N.
,
Wright
,
J. D.
,
Moldover
,
M. R.
, and
Espina
,
P. I.
, 2003, “
Temperature Characterization in the Collection Tank of the NIST 26m3 PVTt Gas Flow Standard
,”
Metrologia
0026-1394,
40
, pp.
211
216
.
11.
Stoup
,
J. R.
, and
Doiron
,
T. D.
, 2001, “
The Accuracy and Versatility of the NIST M48 Coordinate Measuring Machine
,”
Proc. SPIE
0277-786X,
4401
, pp.
136
146
.
12.
Taylor
,
B. N.
, and
Kuyatt
,
C. E.
, 1994, “
Guidelines for Evaluating and Expressing the Uncertainty of NIST Measurement Results
,” NIST TN-1297.
13.
ISO
, 1995, “
Guide to the Expression of Uncertainty in Measurement
,”
International Organization for Standardization (ISO)
, Geneva, Switzerland.
14.
John
,
J. E.
, 1984,
Gas Dynamics
,
2nd ed.
,
Allyn and Bacon
,
Boston
.
15.
Tang
,
S.
, 1969, “
Discharge Coefficients for Critical Flow Nozzles and Their Dependence on Reynolds Numbers
,” Ph.D. thesis, Princeton University, Princeton, NJ.
16.
Geropp
,
D.
, 1971, “
Laminare Grenzschichten in Ebenen und Rotationssymmetrischen Lavalduesen
,” Deutsche Luft-Und Raumfart, Forschungsbericht, pp.
71
90
.
17.
Stratford
,
B. S.
, 1964, “
The Calculation of the Discharge Coefficient of Profiled Choked Nozzles and the Optimum Profile for Absolute Air Flow Measurement
,”
J. R. Aeronaut. Soc.
0368-3931,
68
, pp.
237
245
.
18.
Hall
,
I. M.
, 1962, “
Transonic Flow in Two-Dimensional and Axially-Symmetric Nozzles
,”
Q. J. Mech. Appl. Math.
0033-5614,
15
, pp.
487
508
.
19.
Kliegel
,
J. R.
, and
Levine
,
J. N.
, 1969, “
Transonic Flow in Small Throat Radius of Curvature Nozzles
,”
AIAA J.
0001-1452,
7
, pp.
1375
1378
.
20.
Johnson
,
R. C.
, 1964, “
Calculations of Real-Gas Effects in Flow Through Critical Nozzles
,”
ASME J. Basic Eng.
0021-9223,
86
, pp.
519
526
.
21.
Back
,
L. H.
, and
Cuffel
,
R. F.
, 1971, “
Flow Coefficients for Supersonic Nozzles With Comparatively Small Radius of Curvature Throats
,”
J. Spacecraft
,
8
(
2
), pp.
196
198
.
22.
Smith
,
R. E.
, and
Matz
,
R. J.
, 1962, “
A Theoretical Method of Determining Discharge Coefficients for Venturis Operating at Critical Flow Conditions
,”
ASME J. Basic Eng.
0021-9223,
84
(
4
), pp.
434
446
.
23.
Massier
,
P. F.
,
Back
,
L. H.
,
Noel
,
M. B.
, and
Saheli
,
F.
, 1970, “
Viscous Effects on the Flow Coefficient for a Supersonic Nozzle
,” AIAA Technical Note, pp.
605
607
.
24.
Ishibashi
,
M.
, and
Takamoto
,
M.
, 1997, “
Very Accurate Analytical Calculation of the Discharge Coeffcients of Critical Venturi Nozzles With Laminar Boundary Layer
,”
Proceedings of the FLUCOME
,
Hayama, Japan
, Sept. 14.
25.
White
,
F. M.
, 1991,
Viscous Fluid Flow
,
McGraw-Hill
,
New York
.
26.
Johnson
,
A. N.
,
Wright
,
J. D.
,
Nakao
,
S.
,
Merkle
,
C. L.
, and
Moldover
,
M. R.
, 2000, “
The Effect of Vibrational Relaxation on the Discharge Coefficient of Critical Flow Venturis
,”
Flow Meas. Instrum.
0955-5986,
11
(
4
), pp.
315
327
.
27.
Johnson
,
A. N.
, 2000, “
Numerical Characterization of the Discharge Coefficient in Critical Nozzles
,” Ph.D. thesis, Pennsylvania State University, University Park, PA.
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