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Coriolis flowmeters: A review of developments over the past 20 years, and an assessment of the state of the art and likely future directions
This paper starts from a brief revisit of key early published work so that an overview of modern Coriolis flowmeters can be provided based on a historical background. The paper, then, focuses on providing an updated review of Coriolis flow measurement technology over the past 20 years. Published research work and industrial Coriolis flowmeter design are both reviewed in details. It is the intention of this paper to provide a comprehensive review study of all important topics in the subject, which include interesting theoretical and experimental studies and innovative industrial developments and applications. The advances in fundamental understanding and technology development are clearly identified. Future directions in various areas together with some open questions are also outlined.This is the accepted manuscript version. The final version is available from Elsevier at http://dx.doi.org/10.1016/j.flowmeasinst.2014.08.01
Gas-liquid Two-phase Flow Measurement Using Coriolis Flowmeters Incorporating Artificial Neural Network, Support Vector Machine and Genetic Programming Algorithms
Coriolis flowmeters are well established for the mass flow measurement of single phase flow with high accuracy. In recent years attempts have been made to apply Coriolis flowmeters to measure two-phase flow. This paper presents data driven models that are incorporated in Coriolis flowmeters to measure both the liquid mass flowrate and the gas volume fraction of a two-phase flow mixture. Experimental work was conducted on a purpose-built two-phase flow test rig on both horizontal and vertical pipelines for a liquid mass flowrate ranging from 700 kg/h to 14500 kg/h and a gas volume fraction between 0 and 30%. Artificial Neural Network (ANN), Support Vector Machine (SVM) and Genetic Programming (GP) models are established through training with experimental data. The performance of BP-ANN (Back Propagation - ANN), RBF-ANN (Radial Basis Function - ANN), SVM and GP models is assessed and compared. Experimental results suggest that the SVM models are superior to the BP-ANN, RBF-ANN and GP models for two-phase flow measurement in terms of robustness and accuracy. For liquid mass flowrate measurement with the SVM models, 93.49% of the experimental data yield a relative error less than ±1% on the horizontal pipeline whilst 96.17% of the results are within ±1% on the vertical installation. The SVM models predict gas volume fraction with a relative error less than ±10% for 93.10% and 94.25% of the test conditions on horizontal and vertical installations, respectively
Industrial flow measurement
This thesis discusses the intrinsic worth of a published work, ‘Industrial Flow
Measurement’ (Appendix A), a handbook written and revised by the author over a
period of 30 years. The author first discusses the need to measure flow and then
moves on to the raison dâ€™Ăªtre of the handbook before looking at a brief history of flow
measurement. Although not claiming that any single attribute of the handbook is
unique, the author nonetheless postulates that because it incorporates several
distinctive features, at a number of different levels, these agents combine to make it
one-of-a- kind.
The author moves on to an overview of existing flow metering technologies discussed
within the handbook. Finally, he looks at what he considers is a major gap in the
collected body of knowledge – the field of multiphase and water-cut metering and
provides a justification, not only for its inclusion in the future but for future
investigation
Experimental investigations of two-phase flow measurement using ultrasonic sensors
This thesis presents the investigations conducted in the use of ultrasonic
technology to measure two-phase flow in both horizontal and vertical pipe flows
which is important for the petroleum industry. However, there are still key
challenges to measure parameters of the multiphase flow accurately. Four
methods of ultrasonic technologies were explored.
The Hilbert-Huang transform (HHT) was first applied to the ultrasound signals of
air-water flow on horizontal flow for measurement of the parameters of the two-
phase slug flow. The use of the HHT technique is sensitive enough to detect the
hydrodynamics of the slug flow. The results of the experiments are compared
with correlations in the literature and are in good agreement.
Next, experimental data of air-water two-phase flow under slug, elongated
bubble, stratified-wavy and stratified flow regimes were used to develop an
objective flow regime classification of two-phase flow using the ultrasonic
Doppler sensor and artificial neural network (ANN). The classifications using the
power spectral density (PSD) and discrete wavelet transform (DWT) features
have accuracies of 87% and 95.6% respectively. This is considerably more
promising as it uses non-invasive and non-radioactive sensors.
Moreover, ultrasonic pulse wave transducers with centre frequencies of 1MHz
and 7.5MHz were used to measure two-phase flow both in horizontal and
vertical flow pipes. The liquid level measurement was compared with the
conductivity probes technique and agreed qualitatively. However, in the vertical
with a gas volume fraction (GVF) higher than 20%, the ultrasound signals were
attenuated.
Furthermore, gas-liquid and oil-water two-phase flow rates in a vertical upward
flow were measured using a combination of an ultrasound Doppler sensor and
gamma densitometer. The results showed that the flow gas and liquid flow rates
measured are within ±10% for low void fraction tests, water-cut measurements
are within ±10%, densities within ±5%, and void fractions within ±10%. These
findings are good results for a relatively fast flowing multiphase flow
Two-phase slug flow measurement using ultra-sonic techniques in combination with T-Y junctions
The accurate measurement of multiphase flows of oil/water/gas is a critical element
of oil exploration and production. Thus, over the last three decades; the development
and deployment of in-line multiphase flow metering systems has been a major focus
worldwide. Accurate measurement of multiphase flow in the oil and gas industry is
difficult because there is a wide range of flow regimes and multiphase meters do not
generally perform well under the intermittent slug flow conditions which commonly
occur in oil production.
This thesis investigates the use of Doppler and cross-correlation ultrasonic
measurements made in different high gas void fraction flow, partially separated
liquid and gas flows, and homogeneous flow and raw slug flow, to assess the
accuracy of measurement in these regimes.
This approach has been tested on water/air flows in a 50mm diameter pipe facility.
The system employs a partial gas/liquid separation and homogenisation using a T-Y
junction configuration. A combination of ultrasonic measurement techniques was
used to measure flow velocities and conductivity rings to measure the gas fraction. In
the partially separated regime, ultrasonic cross-correlation and conductivity rings are
used to measure the liquid flow-rate. In the homogeneous flow, a clamp-on
ultrasonic Doppler meter is used to measure the homogeneous velocity and combined
with conductivity ring measurements to provide measurement of the liquid and gas
flow-rates. The slug flow regime measurements employ the raw Doppler shift data
from the ultrasonic Doppler flowmeter, together with the slug flow closure equation
and combined with gas fraction obtained by conductivity rings, to determine the
liquid and gas flow-rates.
Measurements were made with liquid velocities from 1.0m/s to 2.0m/s with gas void
fractions up to 60%. Using these techniques the accuracies of the liquid flow-rate
measurement in the partially separated, homogeneous and slug regimes were 10%,
10% and 15% respectively. The accuracy of the gas flow-rate in both the
homogeneous and raw slug regimes was 10%. The method offers the possibility of
further improvement in the accuracy by combining measurement from different
regimes
Support of gas flowmeter upgrade
A project history review, literature review, and vendor search were conducted to identify a flowmeter that would improve the accuracy of gaseous flow measurements in the White Sands Test Facility (WSTF) Calibration Laboratory and the Hydrogen High Flow Facility. Both facilities currently use sonic flow nozzles to measure flowrates. The flow nozzle pressure drops combined with corresponding pressure and temperature measurements have been estimated to produce uncertainties in flowrate measurements of 2 to 5 percent. This study investigated the state of flowmeter technology to make recommendations that would reduce those uncertainties. Most flowmeters measure velocity and volume, therefore mass flow measurement must be calculated based on additional pressures and temperature measurement which contribute to the error. The two exceptions are thermal dispersion meters and Coriolis mass flowmeters. The thermal dispersion meters are accurate to 1 to 5 percent. The Coriolis meters are significantly more accurate, at least for liquids. For gases, there is evidence they may be accurate to within 0.5 percent or better of the flowrate, but there may be limitations due to inappropriate velocity, pressure, Mach number and vibration disturbances. In this report, a comparison of flowmeters is presented. Candidate Coriolis meters and a methodology to qualify the meter with tests both at WSTF and Southwest Research Institute are recommended and outlined
Complex Signal Processing for Coriolis Mass Flow Metering in Two-Phase Flow
This paper presents a new signal processing method based on Complex Bandpass
Filtering (CBF) applied to the Coriolis Mass Flowmeter (CMF). CBF can be
utilized to suppress the negative frequency component of each sensor signal to
produce the corresponding analytic form with reduced tracking delay. Further
processing of the analytic form yields the amplitude, frequency, phase and
phase difference of the sensor signals. In comparison with previously published
methods, CBF offers short delay, high noise suppression, high accuracy and low
computational cost. A reduced delay is useful in CMF signal processing
especially for maintaining flowtube oscillation in two/multi-phase flow
conditions. The central frequency and the frequency range of the CBF method are
selectable so that they can be customized for different flowtube designs
Application of Soft Computing Techniques to Multiphase Flow Measurement: A Review
After extensive research and development over the past three decades, a range of techniques have been proposed and developed for online continuous measurement of multiphase flow. In recent years, with the rapid development of computer hardware and machine learning, soft computing techniques have been applied in many engineering disciplines, including indirect measurement of multiphase flow. This paper presents a comprehensive review of the soft computing techniques for multiphase flow metering with a particular focus on the measurement of individual phase flowrates and phase fractions. The paper describes the sensors used and the working principle, modelling and example applications of various soft computing techniques in addition to their merits and limitations. Trends and future developments of soft computing techniques in the field of multiphase flow measurement are also discussed
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