Accurate Flow Rate Measurement Research Articles

Modeling of the discharge coefcient of diferential pressure fowmeters: approximation by using radial-basis function neural networks

The discharge coefficient of flow transducers of liquids and gases of differential pressure flowmeters plays an important role in flow rate measurement. The problem of modeling and calculating the discharge coefficient of differential pressure flowmeters directly affects the accuracy of flow rate measurement of these devices. The results of modeling the discharge coefficient of the differential pressure flowmeter in the form of radial-basis neural networks are presented. The described structure of the neural network calculates the values of the discharge coefficient with an angular pressure tapping method. The article evaluates the error of approximation of the discharge coefficient by radial-basis function networks and provides recommendations for building such networks to solve problems of modeling the characteristics of differential pressure flowmeters. The article discusses the main advantages and disadvantages of using such networks as discharge coefficients of the differential pressure flowmeters. The research showed that the use of such networks is justified by their properties to approximate the discharge coefficient and their efficiency in measuring gas and liquid flow rates.

Flow Performance Analysis of Non-Return Multi-Door Reflux Valve: Experimental Case Study

Non-return multi-door reflux valves are essential in fluid control systems to prevent reverse flow and maintain system integrity. This study experimentally analyzes the flow performance of multi-door check valves under different operating conditions, focusing on pressure testing and evaluating their effectiveness in preventing backflow. A wide-ranging experimental setup was designed and implemented to simulate real-world scenarios, facilitating accurate measurement of flow rates, pressure differences, and valve response times. The collected experimental data were analyzed to evaluate the valve’s performance in terms of flow capacity, pressure drop, and hydraulic efficiency. Additionally, the effects of factors such as valve size, valve configuration, and fluid properties (water) on performance were considered. It was found that the non-return multi-door reflux valve has been proven effective and reliable in preserving system integrity and maintaining unidirectional flow at the same time during pressure testing. It exhibits no backflow, remains stable and constant across varied flow conditions, and demonstrates a low pressure drop and high flow capacity, making it suitable for critical pressure testing applications. The response curve revealed that valve opening takes longer to reach higher flow rates than closing, indicating pressure instability during transition periods. This non-linear relationship indicates possible irregularities in pressure drop response to flow rate changes, highlighting potential areas for further investigation.

A New Development of Cross-Correlation-Based Flow Estimation Validated and Optimized by CFD Simulation

The accurate measurement of mass flow rates is important in nuclear power plants. Flow meters have been invented and widely applied in several industries; however, the operating environment in advanced nuclear power plants is especially harsh due to high temperatures, high radiation, and potentially corrosive conditions. Traditional flow meters are largely limited to deployment at the outlet of pumps, on pipes, or in limited geometries. Cross-correlation function (CCF) flow estimation, on the other hand, can estimate the flow velocity indirectly without any specific instruments for flow measurement and in any geometry of the flow region. CCF flow estimation relies on redundant instruments, typically temperature sensors, in series in the direction of flow. One challenge for CCF flow estimation is that the accuracy of the flow measurement is mainly determined by inherent, common local process variation across the sensors, which may be small compared to the uncorrelated measurement noise. To differentiate the process variations from the uncorrelated noise, this research implements periodic fluid injection at a different temperature than the bulk fluid before the temperature sensors to amplify process variation. The feasibility and accuracy of this method are investigated through flow loop experiments and Computational Fluid Dynamics (CFD) simulations. This paper focuses on a CFD simulation model to verify the previous experimental results and optimize CCF flow estimation with different configurations. The optimization study is carried out to perform a grid search on the optimal location of the sensor pair under different flow rates. The CFD results show that the optimal sensor spacing depends on the flow rate being measured and provides guidance for sensor location implementation under various anticipated flow rates.

Research on soft measurement model of flow in bends of primary circuits of the nuclear power plant

When measuring the coolant flow in a nuclear power plant using the elbow flowmeter, the complex fluid-heat coupling environment at the measurement location and other factors will affect the accuracy of the flow measurement, and the uncertainty of the influencing factors on the flow measurement needs to be considered to improve the measurement accuracy. To address this problem, this paper adopts the finite element simulation method to simulate and analyze the flow-heat field of the bend section of the primary circuit of a nuclear power plant and optimizes the Optimal Cross-section selection of the pipeline for flow measurement. Based on the pressure values measured using the traditional method, temperature information is added, and a BP neural network bend pipe flow soft measurement model based on the whale optimization algorithm is established to quantify the effects of temperature and pressure on flow measurement. The experimental results show that compared with the traditional engineering empirical method, the average absolute percentage error measured by the soft measurement method is reduced from 2.57 % to 0.21 %, which realizes the accurate measurement of the coolant flow rate of the elbow pipe.

Numerical approach for investigating the influence of various flow and fluid parameters on the performance of a cryogenic two-phase flow meter

Despite the intricacy, inline metering of two-phase flow has a significant impact in multitudinous applications, including nuclear fusion reactors, particle accelerators, and other systems that use cryogenic fluids. In this regard, a new concept for two-phase flow metering has been developed using model fluids. However, the geometric configurations of the channels and fluid properties are pivotal in ensuring accurate flow rate measurement. In this study, numerical analysis are performed to investigate the influence of channel width, number of channels, and gravitational field on the performance of the flow meter. The liquid height extracted from the volume fraction contour using an image processing tool has been used for calculating the mass flow rate of the liquid. The measured flow rate has been compared with the theoretical data, and it shows acceptable correspondence within ±6 %. The investigations suggest that the increase in channel width governs the slope development. The appropriate width of the channel has been found to be ranging between 1 mm and 3 mm for the selected flow conditions and configurations. It is found that as the number of channels is increased from 10 to 20, the flow rate range that the system can measure within ±5 % error has increased from 250 g/s to 450 g/s. The analysis broadened the reliability of the supposition and, therefore, provided a sturdy base for developing a cryogenic two-phase flow meter.

Numerical and experimental investigation on droplet entrainment mechanism and closed equations of two-fluid model

As a clean and low-carbon energy source, natural gas is an important force in achieving carbon peaking and carbon neutrality goals. Affected by the strong force of gas and liquid during mining and transportation, it exhibits the phenomenon of droplet entrainment. Entrained droplets change the properties of gas and liquid phases, which is crucial for accurate measurement of liquid film thickness, gas holdup, pressure drop and flow rates in natural gas pipelines. The measurement of entrained droplets has always been a focus and difficulty in the two-phase flow research field. Therefore, numerical simulation combined with experimental measurement are presented to study the droplet entrainment mechanism and closed equations of two-fluid model. The specific parameter settings for simulating horizontal gas–liquid annular flow based on numerical method are discussed, and effective simulation of droplet entrainment and deposition in annular flow is achieved. By comparing liquid film thickness and wave velocity from the simulation results with the experimental results, the correctness of the simulation method is verified. Then, the mechanism and dynamic evolution process of entrained droplets in annular flow are revealed, and the generation and deposition characteristics of entrained droplets are studied. As a result, the closed equations of two-fluid model such as droplet velocity, gas–liquid interface velocity, and gas–liquid interface friction factor are established. The proposed two-fluid model is validated using dual mode ultrasound and differential pressure sensors, demonstrating its good applicability and extrapolation.

Accurate measurement of micro gas flow rates for comprehensive evaluation of polymeric membranes applicable in gaseous separations

ABSTRACT The time-lag method is the most useful technique to determine gas permeability, diffusivity, and solubility. However, it is difficult to evaluate the transport properties of the membrane accurately because gas permeability depends on the technique used to assess gas flow. The significance of the present study is to design an economic isochoric apparatus to accurately measure micro-range gas flow rates ranging from 10−6 to 10 cm3(STP) s−1. A strategic procedure is demonstrated to eliminate possible artifacts while conducting the gas permeation experiments, including utilizing downstream pressure rise profiles to identify nanoscale defects as well as transient and steady-state permeation. An indigenous apparatus was developed to estimate the polymeric intrinsic properties of the dense and thin-film composite membranes. The device has been successfully used to measure the gas permeation flow rate ranging from 1 × 10−5 to 1 × 10−1cm3 (STP) s−1, which indicates the broad applicability and reproducibility of the data suggesting the reliability of the designed apparatus. Permeation flow rates of binary mixtures of CO2/CH4 through the defect-free membranes were compared with the numerical estimations to validate the measured transport properties.

Multi-channel gas-diesel engine control system based on jet-convective sensors

Accurate measurement of the dynamic flow rate of the components of the gas-fuel mixture is required in electronic automatic control systems of the internal combustion engine. The paper substantiates the structural construction of the measurement channels of the multi-channel gas-diesel engine control system. In the implementation of the measurement channels, special attention is paid to the structure of the jet-convective channel for obtaining an informative signal on the gas fuel flow rate and the structure of the ion-labeled channel for measuring the air flow rate. Application of jet-convective transducers is supplemented by the original structural scheme of primary signals processing, which will allow expanding the measurement range towards low flow rate values, increasing the speed and reducing the random component of the error.

A new type of velocity averaging tube vortex flow sensor and measurement model of mass flow rate

Accurate mass flow rate measurement of fluid is one of the key technologies to ensure product quality and utilization of energy resources. However, the accuracy of traditional combined measuring devices is limited. In this paper, a new type of velocity averaging tube vortex flow sensor (VATV) is designed, and the mass flow rate measurement model is proposed and analyzed to achieve the high precision measurement of mass flow rate. The size, shape and structure of the VATV are designed in this study and there are no moving parts inside the integrated VATV. The method of double differential pressure is proposed to achieve the measurement of the average differential pressure signal and differential pressure fluctuation signal. Then, the method of Empirical Wavelet Transform (EWT) is used to extract the vortex shedding frequency from the differential pressure fluctuation signal. It indicated that the proposed VATV achieves an accuracy of ±0.50%, and the repeatability is also lower than 0.07%. A remarkable improvement of accuracy is achieved compared to the original combined measurement devices. The proposed sensor shows good prospect for the detection of gas-liquid two-phase flow such as wet stream due to the feature of strong anti-interference, high stability and reliability.

Study on a differential pressure microflow sensor on microfluidic chip

Based on the principle of differential pressure flow measurement, graphene film was used to measure the differential pressure in the micro channel of microfluidic chip and finally to obtain the micro flow rates. The relationship between differential pressure and flow rate in micro channel was studied and validated by CFD simulation. The fiber F-P cavity using graphene film was fabricated as the pressure sensitive structure, and the relationship between the measured pressure and the optical power output from the pressure sensitive structures was studied. The mechanism model used to measure the micro flow rates in the micro channel of microfluidic chip was established, and a sample of micro flow sensor was fabricated. The relationship between various quantities in the process of converting flow rate to optical power was verified through experiments, and the mechanism model established was verified. The experimental results demonstrate that fabricated sample could achieve accurate measurement of micro flow rate in the micro channel of microfluidic chip.

Application of invariance theory methods for measuring the flow rate of natural gas with excess hydrogen sulfide content

The paper presents an invariant method for measuring the flow rate of natural gas with an excess content of hydrogen sulfide, which is based on the principle of multichannelling of the invariance theory. The article describes the structure of the flow measurement system, which allows us to perform separate measurements of hydrogen sulfide flow rate and keep records of the amount of pure gas without hydrogen sulfide. The uncertainty of the flow rate measurement results for individual flow components is estimated. The factors that influence the accuracy of flow rate measurement are investigated, and the design features of the measurement system are discussed. The paper presents the results of experimental studies of the system on gas with excessive content of hydrogen sulfide and mercaptans.

An automatic and integrated self-diagnosing system for the silting disease of drainage pipelines based on SSAE-TSNE and MS-LSTM

The regular detection and diagnosis mechanism for the silting disease of drainage pipelines (SDP) is critical for making dredging decisions and flood forecasting. Simultaneously, there is a complex coupling relationship between the pipeline siltation and the dynamic changes of the inlet and outlet flows. However, the traditional silting detection frameworks of drainage pipelines face difficulties in two aspects, accurate flow rate measurements and efficient and intelligent siltation diagnoses. In this paper, an automatic and integrated self-diagnosing system for the silting disease of drainage pipelines is proposed. First, a gradient penalty generative adversarial network (GPGAN), a target recognition algorithm called guided faster R-CNN (GF R-CNN) and an image segmentation method called parallel multiscale U-Net (PMSU-Net) are introduced to dynamically measure the flow of water in the drainage pipelines. Second, an automatic siltation detection and diagnosis algorithm of SDP is constructed based on a t-SNE stack sparse autoencoder (SSAE-TSNE) and multiscale long short-term memory (MS-LSTM). Then, a full-scale prototype verifies the feasibility of the system. This improved flow measurement algorithm achieves the highest accuracy of 90.32%, and an F1 score of 0.963 in comparison with the other algorithms, and the precision-recall curve was the closest to the top right corner. The error rate of the proposed self-diagnosing system is controlled within 8%, which is far better than the other algorithms. Finally, the system algorithms are embedded in an intelligent platform consisting of an unmanned pipeline measuring device (UPM), an unmanned aerial vehicle (UAV) and a server diagnostic centre. The practical application and test show that the accuracy, precision and response speed of the proposed integrated self-diagnosing system have obvious advantages in the function of siltation detection and diagnosis in drainage pipelines.

Volume flow rate calculation model of non-full pipe multiphase flow based on ultrasonic sensors

In the oil and gas industries, it is crucial to employ appropriate drilling fluids in order to maintain equilibrium of formation pressure throughout the various stages of drilling operations. During the recycling process, the drilling fluid may precipitate gas and as a result exhibit non-full pipe flow upon return to the surface. Accurate measurement of the volume flow rate of the drilling fluid is imperative in obtaining valuable information from the bottom of the well. Commonly, on-site drilling operations use a multiphase target flowmeter in conjunction with an empirical model to rectify calculation results. However, the returned multiphase flow that is not fully in the pipe and its liquid component exhibits corrosive properties, making it a challenge for traditional invasive measurement methods to achieve adequate accuracy over an extended period. Therefore, the theoretical potential of utilizing non-contact ultrasonic sensors for measuring the multiphase volume flow rate of the non-full pipe flow is significant. In this research, an apparent flow velocity calculation model was established by integrating the ultrasonic Doppler shift model and pipeline fluid mechanics utilizing a four-channel ultrasonic array. Subsequently, the invariant scattering convolution—long short-term memory) network was trained on the data-fused ultrasonic signal to identify the liquid level. The velocity-area method was also employed to establish a new multiphase volume flow calculation model. To evaluate the validity of the proposed model, comparison experiments of liquid single-phase flow and liquid–solid two-phase flow were conducted. The experimental results show that, compared with the comparative flow measurement system, the accuracy of the ultrasonic flow measurement system is reduced by 0.965%, the nonlinear error by 2.293%, the average relative error by 2.570%, the standard deviation by 1.395, and the root mean square error by 14.394.

Effect of flow-rate measurement accuracy on unaccounted for gas in transmission networks

Unaccounted-for-Gas (UAG) in modern natural gas transmission networks is a very debated topic among researchers and network managers, since UAG significantly affects the physical and commercial balancing of the network itself. On the technical hand, UAG is caused by the unavoidable errors in measuring and estimating gas quantities in the network and it is either positive or negative. However significant and tendentially positive/negative UAG values often occur in modern networks and this can be ascribed to the rise of systematic errors. Furthermore, cyclic trends of UAG are often observed and the correlation with the accuracy of flow-rate measurements has not been adequately investigated, despite this latter is widely recognized as a crucial issue. In this paper, the rangeability faults of flow-meters installed at the interconnections with regional and city networks have been investigated, together with the effect of the drift of the instrument due to the lack of subsequent calibrations. From the analysis carried out, it was found that about 12% of the average daily flow-rates measured in a whole year at the exit points of the Italian network are below the minimum flow-rate of the flow-meter and that a significant correlation between monthly UAG and the number of flow-meter rangeability faults exists.

A Detection Method for Vortex Precession Frequency Based on MEMS Three-Axis Acceleration Sensor

Swirlmeters are widely used in the wellhead metering of low permeability gas fields in China. However, the swirlmeter’s piezoelectric sensor has difficult distinguishing the vortex precession signal from fluid pulsation noise, pipeline mechanical vibration, and other interference. In this article, in order to detect the vortex precession frequency signal effectively and accurately from the interference noises, a signal detection method based on micro-electro-mechanical systems (MEMS) three-axis acceleration sensor was proposed. According to the difference between the force direction of vortex signal and interference signals, a dual-differential technique based on three-axis measurement is proposed to eliminate interference noises. The radiated interference of electromagnetic noise was eliminated by adding a notch circuit and radio frequency interference filter to the measuring circuit. Then, the sensitivity characteristics of vortex precession with different swirl angles were investigated by numerical simulation and the performance of the method was evaluated by experiments. The results of experiments show that the method proposed in this article can improve the sensor’s capability of anti-interference and widen the measurement range. Further wet gas experimental results show that the vortex precession frequency signal detected by MEMS-three-axis acceleration sensor (TAAS) does not change its linear output law in spite of the presence of liquid phase. Finally, a correction model of the instrument coefficient of the swirlmeter for wet gas measurement was established. The relative errors of the fitting model are within ±2.0%, the mean percentage error (MPE) is 0.17%, and the mean absolute percentage error (MAPE) is 0.81%. The method proposed in this article can improve the ratio of signal to noise of swirlmeter, overcome the influence of interference noise on the precession frequency, and broaden the gas flow measurement range. It realizes the efficient and accurate measurement of the gas flow rate for wet gas flow.

Computing intracoronary blood flow rate under incomplete boundary conditions: Combing coronary anatomy and fractional flow reserve.

Accurate measurement of intracoronary blood flow rate is of great significance for the diagnosis of ischemic heart disease (IHD). Computational fluid dynamic (CFD) method, combining coronary angiography images and fractional flow reserve (FFR), provides a new way to calculate the mean flow rate. However, due to the incomplete boundary conditions obtained by FFR, side branches were ignored which was likely to have a significant impact on the accuracy. In this paper, a novel CFD based method for calculating the mean intracoronary flow rate under incomplete pressure boundary conditions was proposed, in order to improve the accuracy by including the side branches. A pressure-flow curve based flow resistance model was employed to model resistance of the epicardial arteries. A series of steady flow simulations were performed to extract the parameters of the flow resistance model, which implicitly specified constraints for splitting flow between branches and thus enabled the mean intracoronary blood flow rate to be calculated in two or more branches under incomplete pressure boundary conditions. Simulation experiments were designed to validate the proposed method in both idealized and reconstructed 3D models of coronary branches, and the impact of the assumed coefficient of the Murray's Law for splitting flow between branches was also investigated. The mean percentage error of the proposed method was +2.05%±0.04% for idealized models and +2.24%±0.01% for reconstructed models, and it was much lower than that of the method ignoring side branches (+38.48%±10.45% for idealized models and +30.54%±6.12% for reconstructed models). When the assumed coefficient of the Murray's Law was inconsistent with the real blood flow condition, the percentage errors still maintained less than about 3.00%. The proposed method provided an easy and accurate way to measure the mean intracoronary flow rate and would facilitate the accurate diagnosis of IHD.

Analysis of development state of the thermal flow sensors of general, biomedical and ecological designation

The paper analyzed the characteristics of microelectronic flow sensors, which made it possible to draw a number of important conclusions, namely: modern microelectronic thermal flow sensors, and in particular biomedical sensors, are characterized by a significant variety of principles of signal formation - from elementary linear converters based on one sensitive element to non-linear ones ( generation, time-dependent) converters based on matrices of functionally integrated elements. The problem of energy consumption of thermal flow sensors remains relevant. This is especially characteristic when powering destination sensors from autonomous, i.e., small-sized, low-power, low-voltage electrochemical cells. A decrease in energy consumption (power and heating temperature) leads to the parasitic effect of signal line resistances and, as a result, to the deterioration of functional characteristics, in particular, to a decrease in the accuracy of flow rate measurement.

Design of signal processing circuit for acoustic Doppler Current Profiler

according to the measurement principle and performance requirements of acoustic Doppler velocity profile, a circuit for weak frequency signal processing is designed. The measurement principle, circuit structure, data comparison before and after signal processing and frequency measurement accuracy data analysis are introduced. The performance comparison and application of the instrument are carried out according to the relevant standards. The experimental results show that the signal processing circuit realizes the constant amplitude amplification of the wide dynamic range frequency signal, and the processed signal is converted by A / D and then measured by digital frequency to obtain a high frequency accuracy. In the application of channel flow measurement, the velocity profile can reflect the change trend of cross-section velocity and complete the accurate measurement of flow rate. It shows that the flow profile instrument based on the signal processing circuit can meet the requirements of on-line monitoring of flow velocity and flow of river and channel.

Flow measurement challenges for carbon capture, utilisation and storage

Carbon Capture, Utilisation and Storage (CCUS) is a key element in the United Kingdom Government strategy for reducing carbon dioxide (CO2) emissions. The UK aims to capture and store 10 million tonnes of CO2 each year by 2030.At each stage in the CCUS infrastructure, accurate measurement of the CO2 flow rate is required, over a range of temperatures, pressures, flow rates and fluid phases, where the flow measurement must be validated through a credible traceability chain. The traceability chain provides the underpinning confidence required to verify meter performance, financial and fiscal transactions, and environmental compliance. The UK equivalent of the EU Emissions Trading System (EU ETS) specifies a maximum uncertainty value for CO2 flow measurement. Accordingly, the provision of accurate and traceable flow measurement of CO2 is a prerequisite for an operational CCUS scheme.However, there are currently no CO2 flow measurement facilities, nationally or internationally, providing traceable flow calibrations of gas phase, liquid/dense phase and supercritical phase CO2 that replicate real-world CCUS conditions. This lack of traceable CO2 gas and liquid flow measurement facilities and associated flow measurement standards is a significant barrier to the successful implementation of CCUS projects worldwide.This paper presents an overview of the traceability chain required for CO2 flow measurement in the UK and globally. Current challenges are described along with potential solutions and opportunities for the flow measurement community.

Applicability evaluation of the ultrasonic pulse-train Doppler method on the disturbed flow in a pipe

This manuscript presents an experimental study to evaluate the applicability of the ultrasonic pulse-train Doppler method (UPTD) to the disturbed flow in a pipe. The UPTD can expand the detectable velocity range compared with the conventional ultrasonic pulse Doppler method and has an advantage of trouble-free installation into conventional hardware. Comparative experiments were conducted using two different transducer frequencies, 1 MHz and 4 MHz. The UPTD was only applied to the 4-MHz condition to expand the velocity range fourfold, which is equal to the velocity range of a 1-MHz transducer. The probability density distributions of the measured velocities were almost the same between 1 MHz and 4 MHz, even though the measurement position was not only downstream of a long straight pipe but also downstream 10 or 5 pipe diameters from an obstacle plate. To estimate the influence of aliasing on the velocity measurement for a large fluctuating flow, experiments using a 2-MHz transducer were also conducted. These results indicated that it is possible to estimate the standard deviation of the velocities measured under the aliasing condition, and the accuracy of flow rate measurement decreases when the standard deviation of the velocity exceeds the measurable velocity by approximately twice. Additionally, the flow rate by the 1-MHz transducer was about −2% smaller than that by the 4-MHz transducer for both the straight pipe and disturbed conditions. Through the validation of the influence of the measurement volume between 1 MHz and 4 MHz conditions, the flow rate difference was found to be likely due to the influences of not only the measurement volume but also the standing wave formed by the pulses reflected on the opposite pipe wall.