Use of a conventional orifice-plate meter is typically restricted to measurements of steady flow rates. For any gas flowing within a duct in a pulsatile manner (i.e., large amplitude mass flow rate fluctuations relative to its steady-in-the-mean value), this paper proposes a new and effective approach for obtaining its time-varying mass flow rate at a specified cross section of an orifice meter. The approach requires time-varying (dynamic) pressure difference measurements across an orifice-plate meter, time-averaged mass flow rate measurements from a separate device (e.g., Coriolis meter), and a dynamic absolute pressure measurement. Steady-in-the-mean turbulent gas flows (Reynolds number ≫2300) with low mean Mach numbers (<0.2) exhibit effectively constant densities over long time-durations and are often made pulsatile by the presence of rotary or oscillatory devices that drive the flow (compressors, pumps, pulsators, etc.). In these pulsatile flows, both flow rate and pressure-difference fluctuation amplitudes at or near the device driver frequency (or its harmonics) are large relative to their steady mean values. The time-varying flow rate values are often affected by transient compressibility effects associated with acoustic waves. If fast Fourier transforms of the absolute pressure and pressure-difference measurements indicate that the predominant frequency is characterized by fp, then the acoustic effects lead to a nonnegligible rate of change of stored mass (associated with density changes) over short time durations (∼ 1/fP) and modest volumes of interest. As a result, for the same steady mean mass flow rate, the time variations (that resolve these density changes over short durations) of mass flow rates associated with pulsatile (and turbulent) gas flows are often different at different cross sections of the orifice meter (or duct). Together with the experimental measurements concurrently obtained from the three recommended devices, a suitable computational approach (as proposed and presented here) is a requirement for effectively converting the experimental information on time-varying pressure and pressure-difference values into the desired dynamic mass flow rate values. The mean mass flow rate measurement assists in eliminating variations in its predictions that arise from the use of turbulent flow simulation capabilities. Two independent verification approaches establish that the proposed measurement approach works well.

References

References
1.
Association Francaise de Normalisation,
2003
, “
Measurement of Fluid Flow by Means of Pressure Differential Devices Inserted in Circular-Cross Section Conduits Running Full, Part II: Orifice Plates
,” European Standard.
2.
Baker
,
R. C.
,
2009
,
Flow Measurement Handbook: Industrial Designs, Operating Principles, Performance, and Applications
,
Cambridge University Press
,
Cambridge, UK
.
3.
McKee
,
R.
,
1989
, “
Pulsation Effects on Orifice Metering Considering Primary and Secondary Elements
,”
Proc. Proceedings of the 22nd Gulf Coast Measurements Short Course
, pp.
112
118
.
4.
Gajan
,
P.
,
Mottram
,
R. C.
,
Hebrard
,
P.
,
Andriamihafy
,
H.
, and
Platet
,
B.
,
1992
, “
The Influence of Pulsating Flows on Orifice Plate Flowmeters
,”
Flow Meas. Instrum.
,
3
(
3
), pp.
118
129
.10.1016/0955-5986(92)90028-4
5.
Mosley
,
D. S.
,
1966
, “
Measurement Error in the Orifice Meter on Pulsating Water Flow
,”
Proc. ASME Flow Measurement Symposium
, pp.
103
123
.
6.
Mottram
,
R. C.
,
1981
, “
Measuring Pulsating Flows With a Differential Pressure Meter
,”
Proc. Proceedings 2nd International Symposium on Fluid Flow Measurements, Instruments Society of America
, pp.
347
361
.
7.
Mottram
,
R. C.
,
1974
, “
The Measurement of Pulsating Flows Using Orifice Plate Meters
,”
Flow: Its Measurements and Control in Science and Industry
R. B.
Dowell
, ed.,
ASME Instruments Society of America
, Chicago, pp.
197
208
.
8.
Kivisalu
,
M.
,
Gorgitrattanagul
,
P.
,
Mitra
,
S.
,
Naik
,
R.
, and
Narain
,
A.
,
2012
, “
Prediction and Control of Internal Condensing Flows in the Experimental Context of Their Inlet Condition Sensitivities
,”
Microgravity Sci. Tech.
,
24
(
3
), pp.
147
155
.10.1007/s12217-011-9287-0
9.
Kivisalu
,
M. T.
,
Gorgitrattanagul
,
P.
,
Narain
,
A.
,
Naik
,
R.
, and
Hasan
,
M.
,
2013
, “
Sensitivity of Shear-Driven Internal Condensing Flows to Pressure Fluctuations and Its Utilization for Heat Flux Enhancements
,”
Int. J. Heat Mass Tran.
,
56
(
1–2
), pp.
758
774
.10.1016/j.ijheatmasstransfer.2012.08.059
10.
Wang
,
G.
, and
Vanka
,
S. P.
,
1995
, “
Convective Heat Transfer in Periodic Wavy Passages
,”
Int. J. Heat Mass Tran.
,
38
(
17
), pp.
3219
3230
.10.1016/0017-9310(95)00051-A
11.
Young
,
L. C.
, and
Finlayson
,
B. A.
,
1976
, “
Mathematical Models of the Monolith Catalytic Converter: Part II. Application to Automobile Exhaust
,”
AIChE J.
,
22
(
2
), pp.
343
353
.10.1002/aic.690220217
12.
Laurantzen
,
F.
,
2010
,
Flow Measuring Technique in Steady and Pulsating Compressible Flows
,
Royal Institute of Technology, KTH Mechanics
,
Stockholm, Sweden
.
13.
Laurantzon
,
F.
,
Örlü
,
R.
,
Segalini
,
A.
, and
Alfredsson
,
P. H.
,
2010
, “
Time-Resolved Measurements With a Vortex Flowmeter in a Pulsating Turbulent Flow Using Wavelet Analysis
,”
Meas. Sci. Technol.
,
21
(
12
), p.
123001
.10.1088/0957-0233/21/12/123001
14.
ANSYS, Inc.,
2009
,
Theory Guide and User Guide ANSYS FLUENT 12.0/12.1 Documentation
.
15.
Davidson
,
L.
,
2003
, “
An Introduction to Turbulence Models
,” Department of Thermo and Fluid Dynamics,
Chalmers University of Technology
,
Gothenburg, Sweden
.
16.
Kundu
,
P. K.
, and
Cohen
,
I. M.
,
2007
,
Fluid Mechanics
,
Academic Press
,
Amsterdam
.
17.
Wilcox
,
D. C.
,
2006
,
Turbulence Modeling for CFD
,
DCW Industries, Inc.
, California.
18.
Bardina
,
J. E.
,
Huang
,
P. G.
, and
Coakley
,
T. J.
,
1997
, “
Turbulence Modeling Validation, Testing, and Development
,”
NASA, Technical Memorandum
No.
110446
.
19.
Kivisalu
,
M.
,
2013
, “Experimental Investigation of Internal Condensing Flows, Their Sensitivity to Pressure Fluctuations and Heat Transfer Enhancements,” Ph.D. thesis,
Michigan Technological University
, Houghton, MI (to be submitted).
20.
Cheesewright
,
R.
, and
Clark
,
C.
,
1998
, “
The Effect of Flow Pulsations on Coriolis Mass Flow Meters
,”
J. Fluid Struct.
,
12
(
8
), pp.
1025
1039
.10.1006/jfls.1998.0176
21.
Vetter
,
G.
, and
Notzon
,
S.
,
1994
, “
Effect of Pulsating Flow on Coriolis Mass Flowmeters
,”
Flow Meas. Instrum.
,
5
(
4
), pp.
263
273
.10.1016/0955-5986(94)90030-2
22.
Thurston
,
G. B.
, and
Martin
,
J. C. E.
,
1953
, “
Periodic Fluid Flow Through Circular Orifices
,”
J. Acoust. Soc. Am.
,
25
(
1
), pp.
26
31
.10.1121/1.1907003
23.
Rice
,
A. F.
,
2012
, “
Assessments and Computational Simulations for a Time-Varying Pulsatile Gas Flow Measurement Technique
,”
M.S. thesis, Michigan Technological University
, Houghton, MI.
24.
Zhao
,
M.
,
2013
, “
Compressible Computational Simulations for a Time-Varying Pulsatile Gas Flow Measurement Technique
,” M.S. thesis,
Michigan Technological University
, Houghton, MI (to be submitted).
You do not currently have access to this content.