Time-of-flight flowmeters offer advantages over other flowmeter types since these are less sensitive to the physical properties of the fluid. However, calibration of the flowmeter for a particular working fluid is still required. A flowmeter that does not require re-calibration with different fluids is desirable in many applications. This paper investigates the performance of a device that measures the time of flight of a heat pulse in a gas stream to determine the flow rate in a pipe. A fusion of the theoretical, experimental, and numerical data is used to suggest a gas-independent correlation function between the response time and flow rate. In particular, the numerical data augmented by the theoretical analysis to account for the wire response time is validated against experimental data and used to further enhance the experimental data set. Nitrogen, helium, and tetrafluoroethane (R134a) are investigated, as these gases provide a wide range of physical and thermodynamic properties. Simulated results match the trends of experimental data well and allow good qualitative analysis. The results also show that using detected pulse width information together with the time of flight can yield a 20% reduction in the errors due to gas type than by using time of flight data alone. This gives a relatively gas-independent function over a dynamic range of 1:400.

References

References
1.
Bradbury
,
L. J. S.
, and
Castro
,
I. P.
, 1971, “
A Pulsed-Wire Technique for Velocity Measurements in Highly Turbulent Flows
,’’
J. Fluid Mech.
,
49
(
4
), pp.
657
691
.
2.
Miller
,
T. E.
, and
Small
,
H.
, 1982, “
Thermal Pulse Time-of-Flight Liquid Flowmeter
,”
Anal. Chem.
,
54
(
6
), pp.
907
910
.
3.
Albert
,
H. J.
, and
Wood
,
R. H.
, 1985, “
High-Pressure, Thermal-Pulse, Liquid Flowmeter
,”
Rev. Sci. Instrum.
,
6
(
10
), pp.
1962
1963
.
4.
Avirav
,
Y.
,
Guterman
,
H.
, and
Ben-Yaakov
,
S.
, 1990, “
Implementation of Digital Signal Processing Techniques in the Design of Thermal Pulse Flowmeters
,”
IEEE Trans. Instrum. Meas.
,
39
(
5
), pp.
761
766
.
5.
vanKuijk
,
J.
,
Lammerink
,
T. S. J.
,
deBree
,
H.
Elwenspoek
,
M.
, and
Fluitman
,
J. H. J.
, 1995, “
Multi-Parameter Detection in Fluid Flows
,”
Sens. Actuators, A: Physical
,
47
(
1–3 372
), pp.
369
3 372
.
6.
Durst
,
F.
,
Al-Salaymeh
,
A.
,
Bradshaw
,
P.
, and
Jovanovic
,
J.
, 2003, “
The Development of a Pulsed-Wire Probe for Measuring Flow Velocity With a Wide Bandwidth
,”
Int. J. Heat Fluid Flow
,
24
(
1
), pp.
1
13
.
7.
Al-Salaymeh
,
A.
, and
Ashhab
,
M. S.
, 2006, “
Modelling of a Novel Hot-Wire Thermal Flow Sensor With Neural Nets Under Different Operating Conditions
,”
Sens. Actuators, A: Physical
,
126
(
1
), pp.
7
14
.
8.
Angelescu
,
D. E.
,
Jundt
,
J.
,
Durivault
,
J.
,
Desbarbieux
,
T.
, and
Mercier
,
B.
, 2007, “
Stochastic Time of Flight Flow Rate Measurement for Microfluidic Applications
,”
Proc. SPIE
,
6465
, pp.
64650X 1
11
.
9.
Al-Salaymeh
,
A.
,
Jovanovic
,
J.
, and
Durst
,
F.
, 2004, “
Bi-Directional Flow Sensor With a Wide Dynamic Range for Medical Application
,”
Med. Eng. Phys.
,
26
(
4
), pp.
623
637
.
10.
Lide
,
D. R.
, ed., 1993,
CRC Handbook of Chemistry and Physics
,
CRC Press
,
Boca Raton
.
11.
DuPont
, 2004, “
Dupont hfc-134a Properties, Uses, Storage and Handling
,” Tech. Rep. H-45945-5,
DuPont Fluorochemicals
, Wilmington, DE.
12.
Eckhardt
,
B.
, 2009, “
Introduction. Turbulence Transition in Pipe Flow: 125th Anniversary of the Publication of Reynolds’ Paper
,”
Phil. Trans. R. Soc. A
,
367
(
1888
), pp.
449
455
.
13.
Kerswell
,
R.
, 2005, “
Recent Progress in Understanding the Transition to Turbulence in a Pipe
,”
Nonlinearity
,
18
, pp.
17
44
.
14.
Zagarola
,
M. V.
, and
Smits
,
A. J.
, 1998, “
Mean-Flow Scaling of Turbulent Pipe Flow
,”
J. Fluid Mech.
,
373
, pp.
33
79
.
15.
Launder
,
B. E.
, and
Spalding
,
D. B.
, 1974, “
The Numerical Computation of Turbulent Flows
,”
Comput. Methods Appl. Mech. Eng.
,
3
, pp.
269
289
.
16.
Bejan
,
A.
, 1993,
Heat Transfer,
John Wiley
,
New York
.
17.
Johnson
,
R.
, ed., 1998,
The Handbook of Fluid Mechanics
,
CRC Press
,
Boca Raton
.
18.
Gilmont
,
R.
, 1996, “
Velocity Profile of Turbulent Flow in Smooth Circular Pipes
,”
Meas. Control
, pp.
96
103
.
19.
Gaskin
,
I.
, 2008, “
CFD Simulation of Thermal Time of Flight Flowmeter
,” Master’s thesis, Cranfield University, Cranfield, UK.
20.
Churchill
,
S. W.
, and
Bernstein
,
M.
, 1977, “
Correlating Equation for Forced Convection From Gases and Liquids to a Circular Cylinder in Crossflow
,”
ASME J. Heat Transfer
,
99
(
2
), pp.
300
306
.
21.
Nakai
,
S.
, and
Okazaki
,
T.
, 1975, “
Heat Transfer from Horizontal Circular Wire at Small Reynolds and Grasshof Numbers— I. Pure Convection
”.
Int. J. Heat Mass Transfer
,
18
, pp.
387
396
.
You do not currently have access to this content.