Accurate Flow Rate Measurement Research Articles

Microfluidic Thermal Flowmeters for Drug Injection Monitoring

This paper presents a microfluidic thermal flowmeter for monitoring injection pumps, which is essential to ensure proper patient treatment and reduce medication errors that can lead to severe injury or death. The standard gravimetric method for flow-rate monitoring requires a great deal of preparation and laboratory equipment and is impractical in clinics. Therefore, an alternative to the standard method suitable for remote, small-scale, and frequent infusion-pump monitoring is in great demand. Here, we propose a miniaturized thermal flowmeter consisting of a silicon substrate, a platinum heater layer on a silicon dioxide thin-membrane, and a polymer microchannel to provide accurate flow-rate measurement. The present thermal flowmeter is fabricated by the micromachining and micromolding process and exhibits sensitivity, linearity, and uncertainty of 0.722 mW/(g/h), 98.7%, and (2.36 ± 0.80)%, respectively, in the flow-rate range of 0.5–2.5 g/h when the flowmeter is operated in the constant temperature mode with the channel width of 0.5 mm. The measurement range of flow rate can be easily adjusted by changing the cross-sectional microchannel dimension. The present miniaturized thermal flowmeter shows a high potential for infusion-pump calibration in clinical settings.

A Survey on High Reynolds Number Pipe Flow for High Accurate Flowrate Measurement Using Ultrasonic Flowmeter

A Survey on High Reynolds Number Pipe Flow for High Accurate Flowrate Measurement Using Ultrasonic Flowmeter

Fuzzy Interpretation of the Discharge Coefficient for the Orifice Plate of Automated Flow Rate Measuring Systems

ABSTRACT Differential pressure flowmeters play a key role in the organization of flow rate measurements of liquids and gases in various industries. Therefore, the tasks related to improving their accuracy and the convenience of forming various dependencies between the values on which the accuracy of flow rate measurement depends are very important. One of the main characteristics that determines the correct and accurate operation of differential pressure flowmeters is the discharge coefficient. In this paper, the authors present a methodology that allows us to present this coefficient as a fuzzy model. The paper presents an original method for modeling the existing discharge coefficient in the form of a fuzzy model that is able to change the existing classical equation. A comparative analysis of the fuzzy and classical models is performed for this discharge coefficient. The article analyzes the errors of the fuzzy model for the discharge coefficient, discusses ways how to reduce the error of the fuzzy model. The proposed methodology describes the application of the fuzzy model for this coefficient within the existing limits for the Reynolds number and diameter ratio. It is shown that for a more accurate approximation of the characteristics, it is necessary to add more fuzzy sets. The present method is feasible for diameter ratio and Reynolds number greater than 5000. The article also discusses the possibilities of using fuzzy models to improve the characteristics of differential pressure flow meters.

Influence of upstream disturbances on performance of an LDV-based cryogenic flow meter standard – CFD modelling and preliminary measurements with air

Increasing trade of liquefied natural gas (LNG) imposes stringent requirements for accurate flow rate measurement of this high energy content fluid. To satisfy this demand, a flow meter has been developed by CEASAME Exadebit which is based on velocity measurement behind a contraction nozzle using Laser Doppler Velocimetry technique (LDV). For this instrument, a calibration factor is defined relating the measured velocity to the flow rate. This calibration factor depends on the Reynolds number and it can be sensitive to the velocity profile behind the nozzle outlet and to presence of upstream flow disturbances such as bends, valves, etc. when the meter is installed on-site. In this paper, CFD modelling, using OpenFoam software, was employed to analyse the sensitivity of the calibration factor to flow disturbances for two types of disturbing elements; a U-bend and half-plate orifice. The CFD model was validated by comparison with experimental data for the calibration factor and velocity profiles obtained from preliminary LDV measurements with air. Two measurement setups were considered where the velocity is measured either in one point at the nozzle axis or integrated along a line across the nozzle diameter. The results show that the considered disturbing elements cause deviations in the calibration factor in the order of tenths of percent and that the maximal sensitivity of the line-setup to these disturbances is approximately half of the maximal sensitivity of the point-setup. On the other hand, it was shown that the line-setup is more sensitive to the LDV positioning than the point-setup.

Pitometry as a validation tool for water flow measurement in large diameter pipelines

Accurate measurement of water flow rates in large diameter pipelines is a challenge for water companies that need to produce, transport and distribute increasing quantities of water. To a large extent, this challenge results from the impossibility of recalibration of the flow meters within the periodicity established in the metrological regulations since the removal of a large size flow meter from its site of operation in the field and its transport to a calibration laboratory is in most cases technically and economically impracticable. Because of this scenario, this paper presents the pitometry technique as an interesting alternative to solve problems related to the validation of water flow measurements performed by flow measurement systems installed in large diameter conduits. The technique is based on the determination of the water flow rate by mapping the velocity profile of the water flow inside the pipe by means of Cole type Pitot tubes. The water flow rate is determined in a cross section of the pipe located near and in series to the flowmeter to be evaluated. Based on the results obtained in a great number of water flow measurements already performed by applying the pitometry technique in large diameter pipelines in the field, it is possible to conclude that this methodology is perfectly applicable in the validation of the performance of flow meters installed in these conduits solving satisfactorily the issues related to its operation.

Evaluating the Improvement of Cross-Correlation–Based Flow Measurement by Periodic Fluid Injection

Nuclear power plants (NPPs) require accurate measurement of mass flow rates. Advanced flowmeters have been widely applied in several current industries; however, the operating environment in NPPs is especially harsh because of high temperature, high radiation, and extremely corrosive conditions. Several of the advanced reactor designs, such as liquid sodium pool reactors and integral small modular reactors, do not have conventional primary piping systems. These designs require an alternative method to accurately measure primary flow. Cross-correlation function (CCF) flow estimation can estimate the flow velocity indirectly without any specific instruments for flow measurement. The target flow rate is derived by the delay time between two sensors located near each other along the flow direction. Temperature sensors are a common choice for this function because they are reliable, economical, and widely used in various industries. The delay time is inferred by applying the CCF to the signals collected from two or more sensors. CCF flow estimation can be performed in any structure of the flow region, not limited to pipes. One challenge for the CCF flow estimation is that the accuracy of the flow measurement is mainly determined by the inherent local process variation, which is small compared to the uncorrelated noise. To differentiate the process variations from the uncorrelated noise, this paper demonstrates periodic fluid injection of a different temperature before the sensors to amplify common process variation. The feasibility and accuracy of this method have been investigated through a physical flow loop experiment designed to verify the CCF flow estimation using fluid injection. Several parameters must be selected when designing the fluid injection CCF measurement system, such as the distance between the fluid injection site and the sensors, the injection period, and the injection flow rate. A series of tests was conducted to investigate whether these parameters were related to the accuracy of the CCF flow estimation and to identify appropriate values for these parameters for different flow regimes. The results show that the fluid injection method improves the flow measurement performance, and the appropriate design of flow injection and measurement geometry produces better flow characterization performance over a range of flow rates.

Mass-Flow-Rate Measurement of Pneumatically Conveyed Particles Through Acoustic Emission Detection and Electrostatic Sensing

Accurate online mass flow rate measurement of pneumatically conveyed particles is desirable to convert a conventional pulverized fuel-fired power station into a smart thermal power plant. This article presents a novel method for the online measurement of the mass flow rate of pulverized fuel through acoustic emission (AE) detection and electrostatic sensing. An integrated sensing head with an AE probe and three sets of electrostatic sensor arrays is developed. The proposed method determines the particle velocity by multichannel cross correlation of the electrostatic signals and extracts the information about mass flow rate from the AE signal arising from impacts of particles with a waveguide protruding into the flow. An analytical model that relates the energy of the AE signals, the particle velocity, and the mass flow rate is established. The sensing head was mounted on the vertical and horizontal sections of a 72-mm bore laboratory-scale test rig conveying fine silica particles. Experimental tests were conducted under a range of flow conditions and installation orientations to assess the performance of the developed measurement system. The results demonstrate that the sensing head should be installed in any orientation away from the elbow on the vertical section of a pipe, while for installation on a horizontal pipe, the waveguide should be in the horizontal direction. The instrumentation system is capable of measuring the mass flow rate of particles in the vertical pipe with a relative error within ±6.5% regardless of the orientation of the sensing head over the mass flow rate from 7 to 25 kg/h and the particle velocity from 12 to 30 m/s, while on the horizontal pipe, the error is within 5.8% when the sensing head is installed with the waveguide in the horizontal direction under the same flow conditions.

Research on Nonlinearity in In situ Calibration of Permanent Magnet Sodium Flowmeter Without Bluff Body

The permanent magnet sodium flowmeter (PMSF) without the bluff body installed on the large-diameter pipe in the fast reactors to measure the sodium coolant flow rate has to be calibrated in situ owing to the degradation of the magnetic field. Since the length of the magnetic field of the PMSF is limited in practical engineering applications, the characteristic between the cross correlation flow rate (CCFR) and the standard flow rate is nonlinear in in situ calibration based on the cross correlation method. Moreover, the nonlinear characteristic has a large repeatability error, which is difficult to apply to in situ calibration. In order to realize the in situ calibration, an “M-type” mean velocity profile in the pipe is obtained by analyzing the influence of the magnetic field on the fluid field. The distribution of the CCFR of the signal at each frequency is analyzed by using the phase-frequency characteristic of the cross-power spectral density (CPSD) of the two signals, and a physical model of the turbulence distribution in the pipe cross section is obtained combining with the “M-type” mean velocity profile. A nonlinearity correction method based on signal frequency band selection is proposed according to the physical model. The in situ calibration experiments of DN150 PMSF without the bluff body are carried out at the sodium temperatures of 400 °C. The signals within 11–20 and 18–35 Hz are used to calculate the CCFR for correcting the nonlinear characteristic, and sodium flow rate measurement accuracy is ±3.0%.

A comprehensive review on accuracy in ultrasonic flow measurement using reconfigurable systems and deep learning approaches

Flow rates of fuel are a major control variable in the engines of airborne vehicles. Accuracy in flow rate measurements became a mandatory requirement for the testing and reliable operation of those engines. Flow rate measurement is also essential in food industries, automotive industries, and chemical industries. Flow rate measurement using ultrasonic transducers is an appropriate choice because of its unique properties when they are in contact with the gases and water medium, as well as larger diameter pipelines. Estimating the echo signal of the ultrasonic flowmeter is a challenging task; however, the processing tasks for real-time performance are mandatory for improving accuracy in flow rate measurements. This article reviews the improvement in the accuracy of flow rate measurements of liquids and gases incorporating the modern technological trends with the support of field programmable gate arrays, digital signal processors, other advanced processors, and deep learning approaches. The review also elaborates on the reduction of uncertainty in single path and multi-path ultrasonic flowmeters. Finally, future research prospects are put forward for developing low cost, reliable, and accurate ultrasonic flowmeters for extensive categories of industrial applications.

Improving sand flow rate measurement of commercial ASDs and comparison with ultrasonic spectral analysis and filtering

Production of sand in gas wells is associated with various issues such as the erosion of pipes, disruption of the gas processing plant and reduced production capacity. Sand production can jeopardise the integrity of the pipes/equipment. Measuring the sand flow rate helps better sand control and management. Currently, there are many concerns about the accuracy of sand flow rate measurement using a commercial acoustic sand detector (ASD). This study suggests a relationship which substantially improves the accuracy of sand flow rate measurement using an ASD. This study also investigates using a simple ultrasonic sensor for sand flow rate measurement in which a fast Fourier transform (FFT) is used to convert data into the frequency domain. When a Savitzky–Golay filter is used on the FFT response, the smoothed output shows that there is a close relationship between the peak value of smoothed FFT signal in the 10–50 kHz frequency range, and the sand flow rate. This relationship provides a more accurate measurement of sand flow rate than is presently available using an ASD.

Theoretical study and experimental measurement of the gas liquid two-phase flow through a vertical Venturi meter

An accurate two-phase flow rate measurement is essential in many applications and industries such as; oil/gas, chemical, pipeline transportation and nuclear industry. This paper presents the findings obtained from two-phase flow rate measurements using Venturi meters coupled with conductance probe sensors. The measurement system and presented methodology can be used to directly and continuously measure the mass flow rate of gas-liquid flows without any need for using a separator. Most of the available data in literature on mass flow rate using Venturis in gas-liquid two phase flows are limited/valid to a certain flow regime. However, the experimental data presented in this paper covered a wide range of flows (i.e. bubbly, slug and churn flows).Three Venturis with different diameter ratios, β = 0.40, β = 0.55 and β = 0.75 have been employed using an air-water vertical test section. The effect of the Venturi’s geometry on the flow behaviour was also evaluated. The average void fraction and void fraction time series have been measured along the test section by nine different conductance probe sensors covering the convergent, throat and divergent sections. In addition, the two-phase pressure drop across the Venturi was measured. Moreover, a new correlation for the gas-liquid slip ratio was proposed in this paper, which is necessary for calculating the two-phase mass flow rate. The proposed slip ratio correlation showed more accuracy than the ones available in literature. It was found that the correlation proposed by Chisholm to predict the two-phase mass flow rate in Venturis with a diameter ratio, β = 0.55, shows the best accuracy among others such as; Murdock, Lin, James and Zhang correlations.

Assessment of Air-Oxygen Blender and Flow Meter Setup in Neonatal Intensive Care Units.

Oxygen therapy is provided in neonatal intensive care units to prevent and treat neonatal hypoxia. This treatment is essential for the physiological development and survival of neonates with respiratory dysfunctions. One method of providing oxygen therapy involves the use of a simple face mask to deliver oxygen-enriched medical air. In these systems, a flow meter is used to adjust the volumetric flow rate of the gas between 5 to 15 L/min. If the flow rate falls below 5 L/min, there is a risk for exhaled carbon dioxide to accumulate in the mask and cause hypercapnia. Several potential hazards have been identified in the configuration of these oxygen therapy systems in neonatal intensive care units that can result in a decrease of flow rate measurement accuracy: the use of an oxygen flow meter to deliver a mixed gas, the orientation of how the flow meter is installed, and a decrease in pressure due to the use of junctions and medical gas hoses. With reduced measurement accuracy at low flow rate settings, clinical users may not be aware that flow rate may drop below 5 L/min. Furthermore, inconsistencies in physical set-up and labelling may result in the wrong gas being delivered to a neonatal patient. To ensure that patient safety is maintained in neonatal intensive care units, a best practice recommendation is provided to address these potential hazards.

Development of Air Flow Rate Prediction Model Using Multiple Regression in VAV Terminal Unit

Accurate measurement of air flow rate is essential in automatic building control using the variable air volume (VAV) system. In order to solve the problems of the existing air flow measurement method and improve the accuracy of air flow control, this study developed a data-based multiple regression air flow prediction model. The independent variables used in the development of the predictive model were selected as the factors used for control and monitoring when operating with variable air flow rate in the existing air conditioning system. Data collection and correlation between independent variables and air flow rate of the terminal unit were analyzed. Using the IBM SPSS statistics version 25, an air flow rate prediction model was developed using multiple regression analysis. Reliability of model was evaluated by comparing the measured airflow. The relative error of −9.3% to 10.4% is shown when comparing the estimated air flow rate by the developed model with the measured air flow rate.

Numerical investigation of the valve-induced disturbance of the performance of a swirl meter

Abstract Flow through a swirl meter is numerically simulated and experimentally investigated to learn the effects of flow disturbance induced by an upstream valve on the performance and internal flow characteristics of the swirl meter. Investigations are performed for five valve openings and three upstream pipe lengths, as the two main influencing factors. Simulation results show that the valve affects the measuring accuracy of the swirl meter by increasing the inlet velocity and thus the internal flow acceleration and vortex precession. Experimental results show that the valve affects the flow rate measurement by as much as 35.7%, falling to ~1% when the valve is opened to 50% or the upstream pipe length is increased to 5 times the pipe diameter. To ensure the effectiveness and accuracy of flow rate measurements, the length of upstream straight pipe between the valve and swirl meter should be at least 5 times the pipe diameter.

Field trial of a modified DFIT (pump-in/flowback) designed to accelerate estimates of closure pressure, reservoir pressure and well productivity index

A problem with the conventional diagnostic fracture injection test (DFIT) design, which involves analysis of the pressure falloff after the pump is shut-off, is the long test times required to achieve closure pressure (pc), a proxy for minimum in-situ stress, and after-closure flow regimes that can be analyzed for reservoir pressure in (pr) and transmissibility.An alternative approach to DFIT implementation is to flowback the injected fluid immediately after the pump is shutdown. Historically this approach has been to accelerate closure only, but recently the authors have demonstrated that careful design of the flowback procedure can yield accelerated pc estimates and possibly reservoir information. The new DFIT is referred to as ‘DFIT-FBA’, where FBA refers to the flowback analysis component to the test. pc is estimated using a Cartesian plot of flowing pressure versus flowback time. pr is determined through flowback data flow regime identification. The well productivity index for the studied reservoir interval is derived using the flowing material balance method. With constraints applied on created fracture properties, reservoir permeability may be determined.The practical application of the DFIT-FBA method is demonstrated with a field trial performed in a western Canadian tight oil reservoir. The resulting DFIT-FBA data quality is excellent yielding both closure and reservoir pressures due to accurate flow rate measurement. Both pressure estimates are in excellent agreement with a conventional DFIT performed on the same zone in the same area, but were obtained in a fraction of the time. In addition, application of the flowing material balance equation to after-closure data yielded an estimate of well productivity index for the tested interval.The DFIT-FBA demonstrated herein allows estimation of properties of interest to completions and reservoir engineers in a fraction of the time of the conventional DFIT.

Non-intrusive flow measurement based on a distributed feedback fiber laser

We propose a new non-intrusive flow measurement method using the distributed feedback fiber laser (DFB-FL) as a sensor to monitor flow in the pipe. The relationship between the wavelength of the DFB-FL and the liquid flow rate in the pipeline is derived. Under the guidance of this theory, the design and test of the flow sensor is completed. The response curve is relatively flat in the frequency range of 10 Hz to 500 Hz, and the response of the flow sensor has high linearity. The flow from 0.6 m3/h to 25.5 m3/h is accurately measured under the energy analysis method in different frequency intervals. A minimum flow rate of 0.046 m/s is achieved. The experimental results demonstrate the feasibility of the new non-intrusive flow measurement method based on the DFB-FL and accurate measurement of small flow rates.

Mass flow rate measurement of bulk solids based on microwave tomography and microwave Doppler methods

Accurate mass flow rate measurement of multiphase flows is a major challenge in the process industry. In this paper, a microwave tomography sensor for the concentration measurement and a microwave Doppler sensor for the velocity measurement are presented for the determination of mass flow rate of gas-solid flows in a pipeline. The method of approach including data acquisition, image reconstruction and short-time FFT is described. With the technique, the concentration of bulk solids in the flow is measured and visualized using the microwave tomography sensor. Based on the velocity and concentration of bulk solids, a time varying mass flow rate can be calculated. The experimental study shows that the mass flow rates measured with the microwave sensors agree well with their actual values. The test results are also presented.

Capacitive sensor and its calibration- A technique for the estimation of solid particles flow concentration

The precise and accurate measurement of flow rate in the batch flow of the solid particles is of primary importance in many process industries for the improvement of the efficiency of the system. Many techniques developed for the measurement of mass flow rate. The capacitive sensors has a significance of being non-invasive, higher accuracy and low cost for mass flow measurement despite the fact that many factors adversely affect the performance- including non-uniform flow, multiphase flow, temperature, pressure, and moisture in the solid particles. This paper covers preliminary investigations of the offline estimation of mass flow concentration based upon the calibration of capacitance electrodes to quantify the mass of dielectric as a function of capacitance variation between the electrodes.

Flow rate measurement in flows with asymmetric velocity profiles by means of distributed thermal anemometry

Flow rate in closed conduits is one of the most frequently measured parameters in industrial processes and in gas and water supply. For an accurate measurement, flow meters typically require a fully developed symmetric flow profile with preferably no radial or tangential velocity components. This is commonly secured by mounting flow meters in a pipe at a sufficiently long distance downstream any change in cross-section or pipe direction. In this paper, we introduce a new approach for flow rate measurement of gases or liquids that employs a novel spatially resolving fluid velocity sensor basing on thermal anemometry. The new principle allows accurate flow rate measurements for non-axisymmetric velocity profiles, even directly after pipe bends, T-junctions or other alterations in the pipe geometry. This is exemplified for air flow in three different pipe bend configurations.

Wet gas over-reading correction for ultrasonic flow meters

Oil and gas operators rely on accurate flow rate measurements to optimize production and generate more from their reservoirs, particularly in wet gas fields. A cost-effective solution for these flow measurements is the use of single-phase measurement technologies with an over-reading correction that corrects the gas flow rate for the presence of the liquid phase. Traditional flow measurement technologies in wet gas fields are Venturi meters and orifice plate meters that involve differential pressure measurements. Over the years, a higher installed base of ultrasonic flow meters is observed in wet gas fields. Ultrasonic flow meters have advantages over conventional wet gas technologies; however, an over-reading correction method for this measurement technology has not yet been derived. The current work is a first attempt to devise a correction method based on a large data set of ultrasonic measurements in horizontal configuration at conditions comparable to field applications. The correction method is a physical model for the gas void fraction and is based on the dominant dimensionless numbers in wet gas flows that originate from the fundamental equations of multiphase flow dynamics. This approach leads to the definition of the over-reading correction in different flow regimes in terms of these dimensionless numbers and is supported by an extensive set of measurement data and evidence from visual observation of the flow patterns. The correction method is capable of correcting the ultrasonic over-reading with a resulting uncertainty of about 4% for a 95% confidence interval for a range of conditions relevant to the oil and gas industry.