Accuracy Of Flowmeters Research Articles

Validation of installation effects of an ultrasonic flow meter on butterfly valve using numerical analysis

Custody transfer in measurement of flow is referred as fiscal metering where the change of ownership involves. Metering errors in custody transfer calls for a rapid improvement in flow measurement technology. However, standard ideal and field real conditions vary due to the constraints such as non-availability of straight length at upstream and downstream piping, disturbances of flow elements of valves, bends etc will lead to variation in accuracy of flow meters do not permit to fulfill this requirement. Flow metering technique such as acoustic method is recommended as complement flow measuring technique for hydro turbines. The motivation of the study is drawn from a typical penstock of hydro plants where the straight lengths on penstocks are generally not available and the flow through the conductor system is regulated by valves. The flow distortion effect of flow elements causes the extent of errors during the flow metering. The numerical and experimental investigations are presented in this paper is to highlight the installation effects and simulate the variation in accuracy for flow rate measurement using clamp on type flow meter by inverse method at the main inlet valve of a hydro turbine. A commercial CFD Fluent solver is used to validate the velocity distortion of the installation on the closed conduit. The CFD analysis is useful for faster analysis on the installation effects where the limitation of time constraints. A reference can be drawn from the results where standard straight lengths are not met. These findings are also useful in selecting a suitable location for the installation of ultrasonic flow meters and helps in identifying the proper location for the installation flow disturbances like bends, valves and spool elements. The findings are useful in eliminating the uncertainty for the performance evaluation of hydro turbines where the flow is one of a vital parameter in improvement of system.

Performing Quality Assurance of Carbon Dioxide for Carbon Capture and Storage

Impurities in carbon dioxide can affect several aspects of the carbon capture and storage process, including storage capacity, rock erosion, accuracy of flow meters, and toxicity of potential leaks. There is an industry need for guidance on performing purity analysis before carbon dioxide is transported and stored. This paper reviews selected reports that specifically provide threshold amount fraction limits for impurities in carbon dioxide for the purpose of transport and storage, with rationales for these limits. A carbon dioxide purity specification is provided (including threshold amount fractions of impurities) on the basis of the findings, as well as recommendations on further work required to develop a suitable gas metrology infrastructure to support these measurements including primary reference materials, sampling methods, and instruments for performing purity analysis. These recommendations provide important guidance to operators and gas analysis laboratories for performing quality assurance.

Investigations on pressure dependence of Coriolis Mass Flow Meters used at Hydrogen Refueling Stations

In the framework of the ongoing EMPIR JRP 16ENG01 “Metrology for Hydrogen Vehicles” a main task is to investigate the influence of pressure on the measurement accuracy of Coriolis Mass Flow Meters (CFM) used at Hydrogen Refueling Stations (HRS). At a HRS hydrogen is transferred at very high and changing pressures with simultaneously varying flow rates and temperatures. It is clearly very difficult for CFMs to achieve the current legal requirements with respect to mass flow measurement accuracy at these measurement conditions. As a result of the very dynamic filling process it was observed that the accuracy of mass flow measurement at different pressure ranges is not sufficient. At higher pressures it was found that particularly short refueling times cause significant measurement deviations. On this background it may be concluded that pressure has a great impact on the accuracy of mass flow measurement. To gain a deeper understanding of this matter RISE has built a unique high-pressure test facility. With the aid of this newly developed test rig it is possible to calibrate CFMs over a wide pressure and flow range with water or base oils as test medium. The test rig allows calibration measurements under the conditions prevailing at a 70MPa HRS regarding mass flows (up to 3.6kgmin−1) and pressures (up to 87.5MPa).

Segmental orifice plates and the emulation of the 90°-bend

AbstractThe 90 ° - bend represents the most common structural element in piping systems and can have a significant impact on the measuring accuracy of flow meters installed downstream. Within the type-approval procedure of water meters, its impact is emulated by means of a segmental orifice plate with a segment area of 7 % (SOP7). In research and development, coverage rates of 33 % (SOP33) or more are sometimes used as an alternative. The purpose of this study is to evaluate the comparability of the flow conditions and their influence on the measurement deviation of flow meters, which is the basic requirement for using SOPs as a substitute for the 90°- bend. We present laser Doppler measurements downstream of an SOP33 and a 90°- bend and describe the flow development in a distance range from 2 to 30 diameters. Besides a quantitative comparison with performance indicators, the measurements are used to model the response of an ultrasonic and electromagnetic flow meter, including recent investigations of an SOP7. The results demonstrate the consistently poor agreement between the SOP7 and the 90°- bend, whereas the SOP33 provides similar flow conditions starting at a distance of 10 diameters. Further studies are necessary to develop a disturbance generator emulating the near-field range.

Improving the structure of two-phase flow meter using feature extraction and GMDH neural network

Determination of the volumetric percentages and type of flow regime in two-phase fluids is a significant parameter in various industries such as oil, gas and petrochemical industries. In current paper, to distinguish this important parameters, the structure consist of one 137Cs source and just one sodium iodide (NaI) detector has been simulated. Three commonly flow regimes including: annular, stratified and homogeneous are simulated in void fraction of 5%–90%. The simulation structure was carried out by the Monte Carlo N Particle X-version (MCNP-X) code to provide the required dataset for extracting the features and using them in the Artificial Neural Network (ANN). The received signal from the detector has many fluctuation, due to the uncertainty of measurements in the MCNPX code. Considering the uncertainty parameter as high-frequency noise and using the Savitzky-Golay filter to eliminate this noise, it has been tried to improve the uncertainty parameter. After denoising the primary signal seven features in time domain were extracted. All the extracted characteristics were considered as the input of the Group Method of Data Handling (GMDH) neural networks. In this research two independent GMDH neural networks were implemented to identify the flow regime and estimate the volumetric percentages. The results indicate that the proposed model has the ability to distinguish the type of flow regimes with 100% precision and determine the volume fraction percentage with the root mean square error of less than 1.11. Reducing the number of detectors, reducing costs, system simplification and increasing the accuracy of two-phase flow meters are the important advantages of this research.

Precise gamma based two-phase flow meter using frequency feature extraction and only one detector

Flow regime information can be used to enhance measurement accuracy of flowmeters. Void fraction measurement and regime identification of two-phase flows including, liquid and gas phases are crucial issues in oil and gas industries. In this study, three different regimes including annular, stratified and homogeneous in the range of 5%–90% void fractions, were simulated by Monte Carlo N-Particle (MCNP) Code. In simulated structure, a Cesium 137 source and only one NaI detector were used to record received transmitted photons. Fast Fourier Transform (FFT) was applied to the registered signals of the detector in order to analyze in the frequency domain. Several features of signals in the frequency domain were extracted. These features were the average value of fast Fourier transform, the amplitude of dominant frequency, variance, Kurtosis and RMS (root mean square). Different combinations of these features were investigated in order to find the best features with the best separation ability for using as the inputs of Artificial Neural Network (ANNs). Two different Multi-Layer Perceptron (MLP) neural networks were used to recognize flow regimes and predict the void fraction. In regime identification procedure, all of the three mentioned regimes were recognized correctly and in the volume fractions prediction procedure, the void fraction was also estimated with a Mean Relative Error (MRE) percentage of less than 0.5%. In all of the previous studies, at least two detectors were used. Using the proposed method in this paper, number of detectors was reduced to one.

Structured methods for improving flow measurement accuracy in pipelines

In the age of digital transformation of production processes in industry and science the development and design of intelligent flow sensors for granular and liquid substances transferring through pipelines becomes more important. With this in view new approaches for improving the accuracy of microwave flowmeters are proposed. Taking into account the characteristics ofelectromagnetic waves propagating through a pipeline, a wave scattered by inhomogeneities of the controlled medium is analyzed. Features of the transformation of the polarized scattered wave limiting the geometric dimensions of the pipeline and optimizing the values of the useful scattered signal are revealed. Expediency of collection of the information signal with orthogonal polarization of the scattered wave and through a directional coupler is substantiated. The method of estimating the measurement accuracy with reference to the signal-to-noise ratio at the input of the processing device is given. The research results can be used in cryogenic machine engineering to measure volume and mass flows of liquid cryogenic products.

Investigating the Ultrasonic Flowmeter Error in Conditions of Distorted Flow Using Multipeaks Salami Functions

Paper is devoted to the problem of improving the accuracy of ultrasonic flowmeters installed in conditions that differ from their calibration conditions. The authors highlighted high sensitivity of ultrasonic flowmeters to distortions of flow structure and large additional error of flowmeters caused by flow distortions. The computer simulations using empirically-derived functions of distorted flow velocity of professor Salami are used to investigate the additional error of flowmeters. The analytical formulas of two- and multi-peaks Salami functions are used in this work to reproduce the distorted flow velocity profile. The authors proposed to determine the calibration factor of the ultrasonic flowmeter using the undistorted component of Salami functions. The values of the calibration factor for the number of acoustic channels from 1 to 6 were calculated using four numerical integration methods: Chebyshev (equidistant location of acoustic paths), Gauss, Gauss-Jacobi, OWICS met­hod. This made it possible to realize the flowrate equation for multi-path ultrasonic flowmeters and to determine their additional error for different location of the acoustic paths. The average flow velocity along each path is calculated based on the flow velocity profile in the pipe cross section. Six two- and multi-peaks Salami functions of velocity are used to calculate the velocity profile of the distorted flow caused by typical local resistances. According to the research results the recommendations were developed for choosing the number of the acoustic paths of the ultrasonic flowmeters and for using the methods for determining the location coordinates of the acoustic paths. We determined the required minimum number of chordal acoustic channels of the ultrasonic flowmeter, which makes it possible to reduce the investigated error to defined limits, even in the presence of complex flow distortions reproduced by Salami multi-peaks functions.

Assessing the effects of local turbulence and velocity profiles on electromagnetic flowmeter accuracy

AbstractWhile various researchers have explored the effects of turbulence profile development on orifice plates, the literature is not clear on how magnetic flowmeters respond to increased levels of local turbulence. Accordingly, this study investigated the effects of local turbulence and velocity profiles on magnetic flowmeter accuracy. Using five magnetic flowmeters from five different manufacturers, laboratory tests were conducted with a flow conditioner located at different distances upstream of the meter. Numerical modeling using commercially available computational fluid dynamics (CFD) software showed local turbulence levels in the pipe to be four times greater at one diameter downstream of a flow conditioner than the local turbulence levels without a flow conditioner installed. Furthermore, the CFD showed that the deviations in flowmeter accuracy were not proportional to the levels of local turbulence.

Comparison of bench test results measuring the accuracy of peak flow meters

BackgroundThe study evaluates and compares the accuracy of nine peak flow meters (“PFMs”) and spirometers that are currently available in Europe and have Conformité Européene (“CE”) marking. The CE marking is a manufacturer’s declaration that their product complies with European health regulations and it is a requirement for marketing medical devices in Europe.MethodsThe nine devices were selected as they all had received or were in the process of receiving CE approval in Europe and were readily obtainable. The devices were bench tested following the ISO 23747:2015 accuracy guidelines for medical devices measuring peak flow. All standards, including accuracy, from these guidelines must be met to obtain CE marking.This study was performed with a certified piston pump testing apparatus. The apparatus chosen was the pulmonary waveform generator manufactured by Piston Medical Ltd. Using predefined flow (time) and volume (time) waveforms, peak flow meters and spirometers were tested for validation and calibration. Three CE guideline tests were utilised, and standards require that all three tests are passed for the device to obtain certification.ResultsOf the nine devices that were tested, two passed and seven failed. The devices that passed the tests were the Smart Peak Flow® and the Mini Wright®.ConclusionsA high percentage of devices failed accuracy testing in this study. This is a concern as the CE marking is a manufacturer’s certification documenting the accuracy, reliability and safety of devices. Of the seven devices that failed all have the CE marking. All tested devices are on the market in Europe based upon studies conducted by each of the manufacturers. The data used to obtain CE certification of these devices, however, are not in the public domain.

Flow Velocity Distribution Towards Flowmeter Accuracy: CFD, UDV, and Field Tests

Inconsistences regarding flow measurements in real hydraulic circuits have been detected. Intensive studies stated that these errors are mostly associated to flowmeters, and the low accuracy is connected to the perturbations induced by the system layout. In order to verify the source of this problem, and assess the hypotheses drawn by operator experts, a computational fluid dynamics (CFD) model, COMSOL Multiphysics 4.3.b, was used. To validate the results provided by the numerical model, intensive experimental campaigns were developed using ultrasonic Doppler velocimetry (UDV) as calibration, and a pumping station was simulated using as boundary conditions the values measured in situ. After calibrated and validated, a new layout/geometry was proposed in order to mitigate the observed perturbations.

Accuracy of Low-cost Flow Meters for Stemflow Observation Including Handmade Tipping Buckets Flow Meter

Accuracy of Low-cost Flow Meters for Stemflow Observation Including Handmade Tipping Buckets Flow Meter

The Effects of a Short‐Radius Elbow on Electromagnetic Flowmeter Accuracy

This study was conducted to show the effects that a short‐radius elbow has on electromagnetic flowmeter accuracy. Previous laboratory studies have shown that non‐ideal piping affects the accuracy of electromagnetic flowmeters. The results of this study indicated that many of the meters tested did not meet their own manufacturer's specified accuracy either in straight pipe or with the required straight pipe installed upstream of the meter and downstream of a short‐radius elbow. However, nearly all meters in this study were repeatable to within ±0.55% when installed in straight pipe. The results illustrate that when a magnetic flowmeter is to be installed in either straight pipe or piping with upstream disturbances, a laboratory calibration will improve the installed accuracy of the meter.

Algorithmic method of the turbo flowmeter accuracy increasing

Algorithmic method of the turbo flowmeter accuracy increasing

A Fourier Collocation Approach for Transit-Time Ultrasonic Flowmeter Under Multi-Phase Flow Conditions

A numerical model for a clamp-on transit-time ultrasonic flowmeter (TTUF) under multi-phase flow conditions is presented. The method solves equations of linear elasticity for isotropic heterogeneous materials with background flow where acoustic media are modeled by setting shear modulus to zero. Spatial derivatives are calculated by a Fourier collocation method allowing the use of the fast Fourier transform (FFT) and time derivatives are approximated by a finite difference (FD) scheme. This approach is sometimes referred to as a pseudospectral time-domain method. Perfectly matched layers (PML) are used to avoid wave-wrapping and staggered grids are implemented to improve stability and efficiency. The method is verified against exact analytical solutions and the effect of the time-staggering and associated lowest number of points per minimum wavelengths value is discussed. The method is then employed to model a complete TTUF measurement setup to simulate the effect of a flow profile on the flowmeter accuracy and a study of an impact of inclusions in flowing media on received signals is carried out.

On accuracy and precision of flowmeters used for oxygen therapy in a veterinary teaching hospital

ObjectiveTo determine the accuracy and precision of flowmeters used for oxygen therapy in a veterinary teaching hospital. Study designAn observational study. MethodsA total of 50 flowmeters used for oxygen therapy were evaluated using Defender 530 gas flow analyzers to measure flow. For each flowmeter, a minimum of seven flow settings were tested in random order and in triplicate. Flow measured at ambient conditions was converted to standardized flow specifications (21.1 °C and 760 mmHg) and analyzed using general linear mixed models. Flowmeters were considered accurate at a given flow setting when the targeted mean flow was within the corresponding 95% confidence interval. Precision of flow was characterized based on the magnitude of variance component estimates. ResultsFlowmeters of 1.0, 3.5 and 8.0 L minute−1 were considered accurate across flow settings corresponding to their capacity range. Flowmeters of 7.0 and 15.0 L minute−1 were accurate at flow settings ≤2.0 L minute−1. For flow settings ≥3.0 L minute−1, average oxygen flow was consistently below reference values. Precision varied with the capacity of the flowmeter, ranked by decreasing precision as 1.0 > 3.5 > 8.0 > 7.0 > 15.0 L minute−1. Conclusions and clinical relevanceA flowmeter of the smallest maximum capacity within the desired flow range is more appropriate for smaller patients where accurate, precise flow delivery is needed. Although 15.0 L minute−1 flowmeters were accurate at flow settings ≤2.0 L minute−1, the graduated increments do not allow exact flow settings <0.5 L minute−1. Flowmeters of 15 L minute−1 capacity should be useful for high-flow oxygen delivery for which accuracy and precision are not critical.

Application of the multichanneling principle for solution of the problems related to increase of substance flowmeter accuracy

This article outlines application of the multichanneling principle to reduce uncertainty in results of fluid and gas flow measurement. It describes the measuring system structure and flow calculation algorithm that allows reducing the uncertainty of flow measurement in conventional flowmeters and achieving invariance of a relatively wider number of medium and system parameters affecting accuracy of flowrate measurement and quantity of substances.

Increasing the Accuracy of Turbine Flow Transducers Using the Method of Generalized Influence Variables

The factors leading to errors in turbine flow transducers are considered. Methods for increasing the accuracy of turbine flow meters are analyzed. A method of generalized influence quantities is proposed, and a variant of its implementation is considered.

Effect of cleaning status on accuracy and precision of oxygen flowmeters of various ages

ObjectiveTo evaluate oxygen flowmeters for accuracy and precision, assess the effects of cleaning and assess conformity to the American Society for Testing Materials (ASTM) standards. Study designExperimental study. MethodsThe flow of oxygen flowmeters from 31 anesthesia machines aged 1–45 years was measured before and after cleaning using a volumetric flow analyzer set at 0.5, 1.0, 2.0, 3.0, and 4.0 L minute−1. A general linear mixed models approach was used to assess flow accuracy and precision. ResultsFlowmeters 1 year of age delivered accurate mean oxygen flows at all settings regardless of cleaning status. Flowmeters ≥5 years of age underdelivered at flows of 3.0 and 4.0 L minute−1. Flowmeters ≥12 years underdelivered at flows of 2.0, 3.0 and 4.0 L minute−1 prior to cleaning. There was no evidence of any beneficial effect of cleaning on accuracy of flowmeters 5–12 years of age (p > 0.22), but the accuracy of flowmeters ≥15 years of age was improved by cleaning (p < 0.05). Regardless of age, cleaning increased precision, decreasing flow variability by approximately 17%. Nine of 31 uncleaned flowmeters did not meet ASTM standards. After cleaning, a different set of nine flowmeters did not meet standards, including three that had met standards prior to cleaning. ConclusionsOlder flowmeters were more likely to underdeliver oxygen, especially at higher flows. Regardless of age, cleaning decreased flow variability, improving precision. However, flowmeters still may fail to meet ASTM standards, regardless of cleaning status. Clinical relevanceCleaning anesthesia machine oxygen flowmeters improved precision for all tested machines and partially corrected inaccuracies in flowmeters ≥15 years old. A notable proportion of flowmeters did not meet ASTM standards. Cleaning did not ensure that they subsequently conformed to ASTM standards. We recommend annual flow output validation to identify whether flowmeters are acceptable for continued clinical use.

Calibration Procedure for Fuel Flow Meters at the Nebraska Tractor Test Lab

Reports in the literature indicated several factors that can influence the accuracy of Coriolis Effect mass flow meters. A Coriolis Effect mass flow meter is used to verify tractor manufacturer‘s fuel consumption claims at the Nebraska Tractor Test Laboratory (NTTL). The accuracy requirement placed on the flow meter by the Organization for Economic Co-operation and Development (OECD) in the Code 2 tractor performance test procedure is not clear, but in the most conservative interpretation is ±0.5% of each flow rate measured. Results showed a dynamic weighing calibration method was not accurate enough to obtain a calibration of the flow meter to the desired accuracy level. A static weighing calibration method developed showed no significant difference between the calibration determined by the flow meter‘s manufacturer with water and the calibration determined by NTTL with No. 2 diesel fuel. Static weighing calibration tests showed that for flow rates at or above 32 kg/h, the flow meter met the ±0.5% error most conservative interpretation of tolerance on flow rate from OECD Code 2.