Ultrasonic Flowmeter Research Articles

A novel approach to multi-path ultrasonic transit time flow meter based on measurement model analysis to improve accuracy

Ultrasonic transit time flow meter (UTTFM) is commonly used in a wide range of applications. It is commonly believed amongst researchers, industrialists, and standard committee members that due to nonuniform flow velocity distribution inside the pipe (flow velocity profile) the measured flow velocity using UTTFM needs to be corrected by the flow profile. Mathematical analysis of UTTFM measured quantity shows that UTTFM measures flow correctly when flow is fully developed or laminar. However, the measurement results using flow profile correction factor produces erroneous values. The UTTFM measurement model assessment shows, when flow is not fully developed, there are unknown quantities contributed by flow velocity in the axial and diametrical direction to measurement results. These unknown quantities lead to erroneous measurement results when it is simply corrected by flow profile. Assessment of the UTTFM error model shows that using multi-path UTTFM can significantly reduce the impact of the unaccounted quantities and improve accuracy. A novel approach to UTTFM design utilizing multiple acoustic paths (using different planes and transmitting angles) is proposed to reduce potential error for UTTFM. This approach is consistent with the general measurement modeling method with incomplete information recommended by JCGM GUM-6:2020.

A miniaturized transit-time ultrasonic flowmeter based on ScAlN piezoelectric micromachined ultrasonic transducers for small-diameter applications

Transit-time ultrasonic flowmeters (TTUFs) are among the most widely used devices for flow measurements. However, traditional TTUFs are usually based on a bulk piezoelectric transducer, which limits their application in small-diameter channels. In this paper, we developed a miniaturized TTUF based on scandium-doped aluminum nitride (ScAlN) piezoelectric micromachined ultrasonic transducers (PMUTs). The proposed TTUF contains two PMUT-based transceivers and a π-type channel. The PMUTs contain 13 × 13 square cells with dimensions of 2.8 × 2.8 mm2. To compensate for the acoustic impedance mismatch with liquid, a layer of polyurethane is added to the surface of the PMUTs as a matching layer. The PMUT-based transceivers show good transmitting sensitivity (with 0.94 MPa/V surface pressure) and receiving sensitivity (1.79 mV/kPa) at a frequency of 1 MHz in water. Moreover, the dimensions of the π-type channel are optimized to achieve a measurement sensitivity of 82 ns/(m/s) and a signal-to-noise ratio (SNR) better than 15 dB. Finally, we integrate the fabricated PMUTs into the TDC-GP30 platform. The experimental results show that the developed TTUF provides a wide range of flow measurements from 2 to 300 L/h in a channel of 4 mm diameter, which is smaller than most reported channels. The accuracy and repeatability of the TTUF are within 0.2% and 1%, respectively. The proposed TTUF shows great application potential in industrial applications such as medical and chemical applications.

Optimize the Rectifier Structure to Improve the Accuracy of Gas Ultrasonic Flowmeter Under Low Flow Conditions

With the promotion of the coal-to-gas policy, the consumption of civil natural gas in China is increasing rapidly. Improving the measurement accuracy of the flowmeter is of great significance in reducing transportation costs. Computational fluid dynamics software (FLUENT) was used for simulation, the upstream choke model of a single elbow pipe was established, and the flow field in the urban pipe network’s transition area was analyzed and optimized to improve the existing commercial flow Conditioner. The effects of the Reynolds number, the installation location of the ultrasonic gas flowmeter, and aperture depth on measurement accuracy were investigated. The results show that installing the flow Conditioner can improve the velocity distribution of the flow field in the pipeline. Optimizing the flow Conditioner can shorten the installation position of the flowmeter. The optimum thickness of the flow Conditioner is 0.25D. The research results provide important theoretical significance and application value for improving the industry’s ultrasonic gas flowmeter measurement accuracy.

Parabolic equation simulation of diffraction effects in a sound beam propagating through a flowing fluid

Ultrasonic transit time difference flow meters are today industrially accepted for custody transfer measurements of oil and for natural gas. Such meters are currently planned to be used also subsea and in remote operations, where the calibration possibilities are few. In such applications the speed of sound measured by these meters will be a powerful input for estimation of density and calorific value of the flowing oil or gas. The ultrasonic transit time measurements in such meters are carried out in a flowing oil or gas, over a range typically between 6 and 40 in. For precise transit time measurements over such ranges, diffraction corrections may be of high importance. Diffraction effects for an acoustic beam generated by a uniform piston source and propagating through a flowing fluid are therefore studied numerically. The flow direction will be perpendicular to the propagation direction of the acoustic beam. The investigation is based on a narrow-angle three-dimensional parabolic equation. Effects both on amplitude and on phase will be presented.

Simultaneous data acquisition for improved performance in transit time difference ultrasonic flowmeters

Clamp-on ultrasonic transit time difference meters have many benefits for use in industry such as their non-intrusive nature, portability and ability to work with corrosive fluids. However, all transit time difference meters suffer from a sensitivity to changes in the speed of sound or flow profile in the fluid during the ultrasonic measurement. Trigger time jitter in the data acquisition electronics can also contribute to fluctuations in the output of the meter, since the upstream and downstream signals jitter back and forth in time independently of one another. Both of these mechanisms are a product of the method of data acquisition used, where one transducer is used as a generator and the signal is received on the other, then the other transducer is driven to send ultrasound the other way. A new method of performing the measurement is proposed in which the transducers are both driven simultaneously and the signal is received on both transducers at the same time, with the ultrasonic waves having passed through the same volume of fluid with the same flow profile. It is shown that fluctuations in the output of a flowmeter at constant flow rate can be reduced by over an order of magnitude compared to acquisition modes where the generation pulse and the start of data acquisition are not actively synchronised.

ON THE USE OF SOUND SPEED FOR EVALUATION OF THE PERFORMANCE OF LIQUID ULTRASONIC FLOW METER IN ZERO FLOW CONDITIONS

At present, ultrasonic flow meters have become well known in custody transfer applications in the petroleum industry. Since facilities for calibration of these meters are costly and limited, methods for performance verification in zero flow conditions have been developed. However, for liquid measurement, a method of zero flow verification is not available yet. In this context, this study presents a new method for zero flow test in liquid ultrasonic flow meters, using a highly accurate instrument as a reference for sound speed. The aim is to evaluate the performance, of a multipath liquid ultrasonic flow meter under different pressures and temperatures, by comparing the calculated sound speed with the result from the reference instrument. Additionally, transit time measurement is also verified in order to account for systematic errors. The experiments were conducted with two test fluids: water and mineral oil, with a maximum deviation of 0.25% during comparison. On the other hand, performing a transit time analysis indicates the presence of systematic errors, meaning that transit times can be adjusted in order to improve the performance of the flow meter. Furthermore, a factorial design is performed to investigate the effect of pressure and temperature, indicating a minimal pressure effect on sound speed when compared to the temperature effect.

Methane Venting at Cold Heavy Oil Production with Sand (CHOPS) Facilities Is Significantly Underreported and Led by High-Emitting Wells with Low or Negative Value.

Cold Heavy Oil Production with or without Sand, CHOP(S), facilities produce a significant portion of Canada's conventional oil. Methane venting from single-well CHOPS facilities in Saskatchewan, Canada was measured (i) using Bridger Photonics' airborne Gas Mapping LiDAR (GML) at 962 sites and (ii) on-site using an optical mass flux meter (VentX), ultrasonic flow meter, and QOGI camera at 11 sites. The strong correlation between ground measurements and airborne GML supported subsequent detailed analysis of the aerial data and to our knowledge is the first study to directly test the ability of airplane surveys to accurately reproduce mean emission rates of unsteady sources. Actual methane venting was found to be nearly four times greater than the industry-reported levels used in emission inventories, with ∼80% of all emissions attributed to casing gas venting. Further analysis of site-total emissions revealed potential gaps in regulations, with 14% of sites appearing to exceed regulated limits while accounting for 61% of measured methane emissions. Finally, the concept of marginal wells was adapted to consider the inferred cost of methane emissions under current carbon pricing. Results suggest that almost a third of all methane is emitted from environmentally marginal wells, where the inferred methane cost negates the value of the oil produced. Overall, the present results illustrate the importance of independent monitoring, reporting, and verification (MRV) to ensure accuracy in reporting and regulatory compliance, and to ensure mitigation targets are not foiled by a collection of disproportionately high-emitting sites.

Validating the design optimisation of ultrasonic flow meters using computational fluid dynamics and surrogate modelling

Domestic ultrasonic flow meters with an intrusive two-stand configuration present a complex flow behaviour due to their unique geometry, which offers an interesting case to evaluate optimisation methods in wall-bounded turbulent flows. In this study, the design and analysis of computer models by computational fluid dynamics is used to predict the turbulent flow and to perform robust design optimisation of the flow meter. The optimisation is accomplished by surrogate modelling based on Kriging, Latin hypercube sampling, and Bayesian strategies to ensure a high-quality and space-filled response surface. A novel function to quantify flow meter measurement uncertainty is defined and evaluated together with pressure drop in order to define the multi-objective optimisation problem. The optimisation Pareto front is shown and compared numerically and experimentally against pressure drop and laser Doppler velocimetry experiments, displaying performance gains and geometrical changes in the 3D space. From the various improved designs sampled experimentally, a 4.9% measurement uncertainty reduction and a 37.4% pressure drop reduction have been shown compared to the analysed baseline case. The applied methodology provides a robust and efficient framework to evaluate design changes, improving ultrasonic flow meters and internal-flow problems with similar features.

Development of microstructures for the formation of metamaterial properties of piezoelectric elements

Microcells were designed for subsequent modeling of piezoelectric and optical elements on their basis. The development of piezoelectric and optical elements from microcells was carried out and models were prepared for 3D printing. These designs can be used in practice as piezoacoustic or piezoelectric sensors if piezoelectric powder is added to their composition, for example, in ultrasonic flow meters, or used to create optical structures, for example, diffractive optical elements. The key characteristics and coefficients of piezoelectric structures, such as dielectric constant, conversion coefficient, dielectric loss coefficient, mechanical Q-factor, frequency constant, electromechanical coupling coefficient, piezoelectric charge coefficient, piezoelectric stress coefficient, elastic compliance coefficient, degradation rate, Curie point are analyzed. Elements produced by 3D printing will have properties different from those of elements produced by standard methods. These structures open up new opportunities for the development of ultrasonic research, mechanical engineering and instrument making.

Development of controllable volumetric prover for evaluating responsiveness of flowmeter under controlled-transient flows

We developed an evaluation system for flowmeter responsiveness, termed “Controllable volumetric prover (CVP),” which can simultaneously measure and control transient flow rate. The control of frequency, amplitude, and wave shape of flow rate work to efficiently evaluate flowmeter responsiveness for transient flow rate. Some analytical methods, such as Lissajous curve plotting, cumulative error calculation, and frequency filter, quantify the responsiveness sufficiently. In this study, to demonstrate the efficacy of the CVP test for evaluating flowmeter responsiveness, an ultrasonic flowmeter is selected as one of the representative examples of the application. CVP test for flowmeters has high potential in evaluating the frequency and amplitude dependence of flow rate measurement and the hysteresis effects during periodic pulsation flows.

Design and Development of Performance Rating Apparatus for Cold Room Refrigeration Unit Using Cooling-Load Balance Method

Refrigeration systems are composed of many components working together, and their refrigerating capacity depends upon these components constituting the refrigeration system. The design of the refrigeration system does not only consider cooling loads from products but also the operating conditions that change from time to time, especially the ambient temperatures due to global warming and climate change. Therefore, this work aims to develop the apparatus for performance rating of the cold room’s refrigeration unit according to the ASHRAE standard test methods as well as the Eurovent certification programs. The principle of enthalpy change is used to determine the system performance, in general. In this work, the cooling-load balanced method is proposed, which shows a good refrigeration capacity estimation by balancing the cooling load with refrigeration capacity. In addition, the use of an ultrasonic flow meter for refrigerant flow rate measurement is also discussed for additional validation in future works.

Water use patterns within each day: Variation between batches of growing pigs in commercial production systems

Objective: To measure, describe, and compare the water use patterns within each day for multiple cohorts of weaner, grower, and finisher pigs in farm buildings. Materials and methods: Prospective, observational cohort studies of the water use patterns within each day were conducted in 5 pig buildings using either a turbine or ultrasonic water flow meter attached to the main water pipe entering each building. Water use data were collected from multiple batches of pigs (second-stage weaners over eleven 48-day periods and grower-finishers over 4 periods of 21-43 days). Semi-parametric models of pig water use patterns within each day were estimated using the brms software package in R. To estimate the interacting effects of time and pig body weight on water use by pigs, we used tensor product smooths for time and pig body weight. Results: The water use pattern within each day varied between the cohorts, and the pattern of many cohorts changed as the pigs gained weight. Some patterns were unimodal and others were bimodal, with the main peak in water use occurring early afternoon to late afternoon. Implications: Water use patterns of pigs within each day varied between and within cohorts. The water use pattern of one cohort cannot be used reliably to predict that of other cohorts, even if they are reared in the same building. Water use pattern data may be valuable for optimizing in-water antimicrobial dosing regimens.

SOFTWARE DEVELOPMENT FOR AUTOMATED DESIGN OF FLOW METERS

This work presents the development of a software complex for the automated design of variable pressure drop flowmeters. It includes flowmeters with standard primary devices, namely a diaphragm, nozzles and a venturi tube. To fulfill the task, a review of various software solutions has been conducted. As a result, it was concluded that the existing software does not fully solve the task, because it does not calculate most of the design parameters for metering device. The next stage was a review of the flow rate measuring method by variable pressure drop, and based on it, a mathematical model of flow meters has been implemented taking into account the existing standards. Next, the initial geometric parameters of the flow meter were evaluated and the parameter selection algorithm for the diaphragm with pressure taking chambers was given.
 As a result of the performed analysis, developed software allows you to conveniently enter input parameters, such as flowrate, pressure drop, pipeline diameter, type of constriction device, method of pressure selection, and at the output receive a corresponding schematic image of the flowmeter with all design parameters and the flow calculation formula, based on the pressure difference. For a better understanding of the software operation, an overview of it was offered and an example of a nozzle calculation has been demonstrated.
 The implementation of the created software application makes it possible to increase the accuracy of the accounting of consumed resources, and also reduces time and money costs for measuring instrument development.
 In the future, it is planned to create the software complex by adding to it the design capabilities of calorimetric, ultrasonic flowmeters and rotameters, as well as special software for selecting the most optimal flow measurement method based on the specified parameters of the measured medium, pipeline diameter and flow measurement range.
 Therefore, it will be possible to carry out metrological control and supervision of such measuring complexes, develop and certify methods for measuring the flow of liquids and gases.

Integration method of multipath ultrasonic flowmeter based on velocity distribution

The error introduced by the integration method greatly affects the measurement accuracy of the multipath ultrasonic flowmeter. In this paper, a multipath ultrasonic flowmeter integration method based on velocity distribution is proposed, taking a DN400 double-side eight-path ultrasonic flowmeter as an example. The velocity distribution function in the plane of the acoustic path is fitted based on the simulated flow field information from the simulation. The integral weight function is determined from the velocity distribution, and the optimal relative path heights and weights are determined within the range. The integration results are compared with that of the traditional Gauss-Jacobi and the OWICS (Optimized Weighted Integration Method for Circular Sections) integration methods. The results show that the proposed method is superior to the traditional integration methods with the integration error reduced to −0.0164%. This integral method is applied to DN393.5 and DN50 multipath ultrasonic flowmeters to verify its applicability.

THE USE OF AN ULTRASONIC FLOW METER IN THE ZONE OF INFLUENCE OF INDIRECT SECTIONS OF THE WATER PIPELINE

The accuracy of water flow rate measurement with an ultrasonic flow meter (UFM) is affected by pipeline conditions. On water pipelines, there is often no the required length of direct section, required by the device passport or regulatory documents. Therefore, we conducted experiments using UFM to measure water flow rate in the zone of influence of non-direct sections of the water pipeline. The flow rate was measured in two planes of the pipeline with an offset of 90 o and the average value was taken. Thus, it was expected to take into account the average water velocity for the asymmetric velocity profile. The results of water flow rate measuring with UFM on short direct sections of the water pipeline, limited by pipeline bends sudden constriction of the pipeline, are presented. The greatest influence on the UFM measurement error is the 90 o pipeline bends.

Algorithm to Correct Measurement Offsets Introduced by Inactive Elements of Transducer Arrays in Ultrasonic Flow Metering

Ultrasonic flow meters (UFMs) based on transducer arrays offer several advantages. With electronic beam steering, it is possible to tune the steering angle of the beam for optimal signal-tonoise ratio (SNR) upon reception. Moreover, multiple beams can be generated to propagate through different travel paths, covering a wider section of the flow profile. Furthermore, in a clamp-on configuration, UFMs based on transducer arrays can perform self-calibration. In this manner, userinput is minimized and measurement repeatability is increased. In practice, transducer array elements may break down. This could happen due to aging, exposure to rough environments, and/or rough mechanical contact. As a consequence of inactive array elements, the measured transit time difference contains two offsets. One offset originates from non-uniform spatial sampling of the generated wavefield. Another offset originates from the ill-defined beam propagating through a travel path different from the intended one. In this paper, an algorithm is proposed that corrects for both of these offsets. The algorithm also performs a filtering operation in the frequency-wavenumber domain of all spurious (i.e., flow-insensitive) wave modes. The advantage of implementing the proposed algorithm is demonstrated on simulations and measurements, showing improved accuracy and precision of the transit time differences compared to the values obtained when the algorithm is not applied. The proposed algorithm can be implemented in both in-line and clamp-on configuration of UFMs based on transducer arrays.

Sonic velocity measurement in molten Pb–Li (16) at high temperature for ultrasonic flowmeter applications

An ultrasonic flowmeter can be a good alternate to electromagnetic flowmeter, being used extensively for high temperature liquid metals. It has an advantage of using it at any location and at any point of time. However, the usage of ultrasonic techniques in high temperature liquid metals is not well established, especially in molten Pb–Li. Pb–Li is considered as a potential coolant candidate in fusion reactor. To study the applicability of ultrasonic techniques in Pb–Li medium with a future scope to develop an ultrasonic flowmeter, a high temperature experimental facility was developed. Sonic velocity was measured in Pb–Li at temperatures ranging from 285 °C to 375 °C using the pulse echo method. It was observed that ultrasonic waves get highly attenuated in molten Pb–Li medium. Out of various tested ways, introduction of W reflector plate could provide detectable reflected signal. The proof of principle test was carried out on few liquids with known values of sonic velocity. The measured sonic velocities have a deviation of ∼6% from that of the reported values.

Development of MEMS Airflow Volumetric Flow Sensing System with Single Piezoelectric Micromachined Ultrasonic Transducer (PMUT) Array

Compared to conventional ultrasonic flowmeters using multiple transducers, this paper reports, for the first time, an airflow volumetric flowmeter using a signal PMUT array to measure the flow rate in a rectangular pipe. The PMUT around 200 kHz is selected to fit the system requirements. All PMUT elements on this single array are then electrically grouped into transmitter and receiver. In order to minimize the crosstalk signal between transmitter and receiver, a phase shift signal is applied at the transmitter to reduce the amplitude of the crosstalk signal by 87.8%, hence, the resultant high sensing resolution. Based on the analog signal extracted from the single PMUT array, a complete flow sensing system is built by using the cross-correlation method and cosine interpolation, whereby the change in flow rate is reflected by the time of flight difference (dTof) recorded at the receiver. Meanwhile, the acoustic path self-calibration is realized by using multiple echoes. Compared with the previously reported MEMS flowmeters with dual or multiple PMUT devices, this paper proposes a single PMUT array flow sensing system, which is able to measure the flow rate changes up to 4 m3/h. With the implementation of a single device, the problem of ultrasound device/reflector misalignment during system setup is completely eradicated.

Womersley's solution for the measurement of volume flow rates in transient laminar flow tubes

The characterization of transient flows within the Reynolds number range of Re = 10–100 and the Womersley number range α = 0.8–10 is required for the ongoing development of green monopropellant thrusters. However, at the ml/min scale flow rates of interest, these measurements are outside the capabilities of current commercial flow meters. It is proposed here that transient flows under the required dynamic conditions can be characterized via Womersley's solution for transient flow in a rigid tube. This solution method requires only the measured transient pressure gradient within a controlled laminar flow section and can be accomplished using existing commercial pressure measurement hardware. Experiments were performed where flow similarity was maintained with the ultimate thruster characterization application, but the radius of the flow passage was increased so that flows could be simultaneously characterized by both the proposed solution method and a commercial ultrasonic flow meter. It was shown that across the range of interest, applying Womersley's solution to a measured pressure gradient was an effective method of transient flow characterization. Additionally, it was shown that non-periodic flows can be characterized except for the initial flow startup transient with solution convergence times approximating the analytical solution to starting flow in a pipe. While these results were expected due to an experimental design matching the assumptions required for Womersley's analytic solution, this work demonstrates that this method is practically feasible as novel instrumentation enabling previously unobtainable measurements.

Robust Flow Estimation Algorithm of Multichannel Ultrasonic Flowmeter Based on Random Sampling Least Squares.

The multi-path ultrasonic flowmeter is widely used in engineering practice, and the flow algorithm is important for its accuracy. The least-squares estimation method is simple and efficient and has good engineering application value. In practical applications, noises are inevitably introduced to the measurement process because of the flowmeter itself or flow-field interference. The results of classical least squares will deviate from reality because it lacks robustness. In this regard, two flow algorithms of multi-path ultrasonic flowmeter are proposed based on least-squares and random-sampling consensus algorithms, which are widely used in the image field. The two algorithms can resist gross errors effectively by avoiding the interference of external points in the sampling points. To verify the effectiveness of the proposed algorithms, we take the double-bend flow field, which is a typical damaged flow field in engineering, as the research object, and then we compare the four algorithms. It can be seen that the two flow algorithms have higher accuracy and better robustness in the presence of interference noise.