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Sun Limin, Zhang Kui, Jiang Chen
Research and application of ultrasonic gas flow meter performance on-line audit

Ultrasonic flow meter has become the mainstream measuring instrument in the natural gas trade because of its advantages of large measuring range, small pressure loss and high measurement accuracy. In the measurement of natural gas with high pressure and large flow, the advantage of ultrasonic flow meter is particularly obvious. Ultrasonic flow meter based on transit-time method can measure the speed of sound and the flow velocity of fluid at the same time. With the continuous improvement of on-site monitoring and diagnosis technology of ultrasonic flow meter, the on-line audit of flow meter based on speed of sound checking has attracted extensive attention. According to AGA No.10 report, the on-line audit based on speed of sound checking was carried out with a 4-path ultrasonic flow meter used in a natural gas station was studied. The studies showed that within 2 years, the signal quality indicators of the ultrasonic flowmeter were basically the same, the variation of flow velocity deviation was within ± 0.5 %, and the variation of the speed of sound deviation of acoustic path was within ± 0.03 %. With the comparison of the real flow calibration, it could be concluded that the metering performance of the flowmeter was stable and reliable, but the installation conditions should be checked to see if they meet the requirements. The results showed that the method of on-line audit can effectively monitor the performance of ultrasonic flowmeter and could be a powerful supplement to the real flow calibration.

Yi ZHOU, Zuoguang ZHAO, Fang DONG, Caihong SUN, Zhi LI
Development of Movable Testing Device for Gas Flow Equipping with the Critical Flow Venturi Nozzles

In order to meet the requirements of rapid on-site verification / calibration of flow meters in our country’s natural gas measurement field, we have jointly developed a movable gas flow testing device equipping with critical flow venturi nozzle. According to actual needs the device will be used in the different lab.In order to ensure the uncertainty of the device can meet the requirements of customers,the designer should fully demonstrates and considers the design in selecting the most suitable temperature and pressure sensor, and the processing of calculus.From technical point, we should control the possible impact on the measurement results of the movablegas flow testing device caused by environmental changes.

I. Gryshanova, A. Rak
Investigation of the Correction Factor for Ultrasonic Flow Meters

The main source of errors while applying modern ultrasonic flow measurement principle is the deviation of the actual velocity profile of the measured flow from the calculated one. If the velocity profile is known, the corresponding correction can be evaluated and considered during calibration. However, in practice, the distribution of velocities in the cross section of the pipeline differs from the theoretical one, which leads to errors of hydrodynamic origin.To determine the flow rate of the measuring medium, it is necessary to transform the flow velocity averaged along the acoustic path to the velocity averaged for the cross section of the flow meter. To do this, use the hydrodynamic correction factor, which is a function of the Reynolds number. The inaccuracy of this factor is the largest component of the total error of ultrasonic flowmeters. This is due to the fact that velocity distribution (and hence the hydrodynamic factor) use dependences obtained on the assumption that measuring flow is axisymmetric and the trajectory of the ultrasonic beam lies in the plane passing through the pipeline axis. Nevertheless, most industrial flow media have a distorted profile due to installation effects, which are an integral part of any hydraulic system. As a result, the determined average flow velocity does not correspond to the real one. Therefore, the problem of studying the influence of flow non-symmetry on the value of the hydrodynamic correction factor is relevant. The effect of distortion of the velocity profile on the measurement results of ultrasonic flowmeters was evaluated using theoretical dependences describing non-symmetric velocity profiles. For this purpose, functions based on the power law of velocity distribution in smooth pipes with the imposition of some influence function, which depends on the radial and angular distances from the observation point to the pipeline axis, were used. However, some dependencies can only be applied to approximate real flow profiles.For velocity profiles that do not have axial symmetry, the only correct way to accurately estimate the flow rate is to reconstruct 2D velocity field using algebraic techniques. The implementation of one of these methods was performed based on the inverse Abel’s transform.For velocity profiles that do not have rotational symmetry around the axis of the pipeline, the value of the measured velocity will depend on the angle of orientation of the measuring plane relative to the diametrical plane of the flow meter. The calculation of the actual average flow velocity in the cross section of the meter was obtained from a specific mathematical dependencies describing velocity distribution by integration technique.This research allows us to conclude that it is possible to calculate the performance of ultrasonic flowmeters under conditions of distorted non-symmetric flows at Re > 104 with sufficient accuracy using computational hydrodynamics, integration based on Abel’s transform, methods of theoretical research and mathematical processing.

A. Rieder, H. Zhu, P. Ceglia, H.-T. Ngo
Laboratory and Field Validation of a New Coriolis Metering Concept for Better Measurement Uncertainty, Reliability and Process Insight

Coriolis mass flowmeters are widely accepted in various industries for the great performance of density and mass flow rate measurements. Not only do they play a critical role in O&G custody transfer applications, but also an increasingly important role in addressing the new challenges and applications related to the energy transition where the highest accuracy and reliability is also required. Analogous to multi-beam Ultrasonic flowmeters, a new measuring concept based on Coriolis principle has been developed with a metering system that consists of two individual Coriolis meters arranged in parallel for the incoming flow in the system. There are numerous advantages of this arrangement, among which reducing measurement uncertainty, increasing reliability and gaining greater process insight are the most significant ones. The statistic theory has shown that for a total measurement equally divided by two sub-measurements of two independent measuring devices, the measurement uncertainty caused by random errors is reduced by a factor of square root of 2 for the combined total measurement. This rule applies to the Zero Point and repeatability performance of the metering system. Taking the advantage of independently measuring the same or similar fluid parameters twice, the measurement reliability is enhanced by cross-checking the two sets of measured parameters. For certain special cases, such as transient disturbance of entrained gas that often exists under real process conditions, the corresponding negative impact can even be mitigated or eliminated by utilizing the undisturbed measured parameter set from the two. The spacial arrangement of the two Coriolis meters makes it useful to monitor the measured fluid parameters such as two sets of densities, flows and temperatures for obtaining the knowledge of the special distribution of fluid parameters, gaining greater process insight.A critical step has been the validation of the theoretical advantages in third-party laboratories and in the field. A test was done for the Zero Point stability of the metering system under various temperatures, pressures and viscosities at NEL using the EPAT facility. The measurement results suggested that the Zero Point deviations of the two Coriolis meters followed a random probability and tended to cancel each other to certain degree, leading to a reduced Zero Point deviation for the complete metering system. Repeatability and reproducibility tests were done both at NEL EPAT and at Euroloop oil rigs with provers, showing good and consistent results. Recognizing most hydrocarbon markets trade on a volumetric basis rather than mass, the advantages the design brings towards density measurement are discussed and measurement data is presented across varying fluid densities and viscosities. In step with the growing importance of gaseous fluids to the evolving energy markets, the influence the novel design has on performance in gas applications is described and measurement data in gases is also presented. Furthermore, an interesting phenomenon has been captured during the flow stabilization phase before proving at Euroloop that transient disturbance of gas bubbles could be present, and very often disturbed only one meter at the same time, which enables the possibility to remediate the effect of transient disturbances. The same phenomenon took place in field tests of the metering system, indicating the high probability of the occurrence. In this paper, the laboratories data from the NEL EPAT rig, Euroloop rig, pigsar rig, and H&D Fitzgerald as well as the data from field applications are presented and analysed to validate the theoretical analysis.

Huichao Shi, Xiao Huang, Tao Meng, Huaiming Shen, Zhiming Yang
Research on error compensation method of multi-channel ultrasonic flowmeter based on SVM

The measurement process of multi-channel ultrasonic flowmeter is affected by the distribution of flow field in the pipeline, which makes the measurement results of sound channel have large errors, and finally leads to large errors in the integration results of flow. Especially when the ultrasonic flowmeter is installed near the rear of the valve, elbow and other spoiler, the influence of the flow field distribution in the pipeline on the measurement results of the ultrasonic flowmeter is difficult to avoid. Aiming at the distribution of the flow field in the pipeline behind the gate valve and its influence on the multi-channel ultrasonic flowmeter, this paper studies the influence of the opening of the gate valve, the distance between the ultrasonic flowmeter and the gate valve and the installation angle of the gate valve on the measurement error of the multi-channel ultrasonic flowmeter through CFD simulation experiments, and puts forward the error compensation model of the multi-channel ultrasonic flowmeter based on SVM, The measurement results of multi-channel ultrasonic flowmeter caused by the flow field distribution behind the gate valve are compensated, and the compensation results are compared with the flow integration results. It is found that the compensation model based on SVM proposed in this paper has better compensation effect.

Song chaofan, Wu yan, Liu zhe, Hao min
Application of integrity management method to improve the management level of gas flow standard facility

To improve the quality control performance on quantity transfer made by gas standard facility, the integrity managementconcept is applied to the quality control of quantity transfer in this study, and a "four-step method" is proposed. Herein,the application of calibrating a critical flow Venturi nozzle(CFN) with the mt gas standard facility is shown as anexample. By applying the four-step method, it is possible to accurately identify the key influencing factors and quantitatively analyze their influence on the measurement results, conduct risk assessment and risk prediction for themeasurement deviation of key measuring instruments and standard facility, and improve the quality control of standard management from passive disposal to active prediction, monitoring and control, so as to realize systematic, refined andintelligent management of standard quantity transfer.

Mengna Li, Chengze Lv, Wenli Li, Chunhui Li
In-use Measurement of Ultrasonic Flowmeter based on Machine Learning

To guarantee the accuracy of ultrasonic flowmeter, an in-use measurement system for ultrasonic flowmeter incorporating digital signal processors and machine learning approaches was proposed. Experimental analysis has been carried out to determine the variables affecting the accuracy of ultrasonic flowmeter. Based on random forest algorithm, we evaluated the contribution of different variables on the accuracy performance of ultrasonic flowmeter, and establish a model including variables extraction and prediction of flow deviationfor in-use measurement of ultrasonic flowmeter. By obtaining data of the flowmeter signal index, flow rate characteristics, sound velocity and flow velocity etc., the flow deviation of ultrasonic flow meter is predicted using random forest algorithm, and the difference between predicated value and observed value is smaller than 0.76 %. Furthermore, the degree of influence of different variables on the accuracy of ultrasonic flowmeter was analysed. The uncertainty of the prediction result was evaluated, with an extended uncertainty U = 0.92 % ~ 0.22 % (k = 2).

Bo Wu, Yong Wan, Bibo Qian, Tao Meng
Research on Technology Status and Development Direction of Large Diameter Water Flow Standard Facility in China

The performance of large diameter water flow facility will have a direct impact on the accuracy and value uniformity of detected flowmeter measurement results. In addition, ensuring the stability and reliability of facility performance has always been a key link in the traceability and transmission of value of large water flow. However, the application scale and measurement capability of existing large diameter facilities are difficult to fully meet social needs. In this paper, based on National Institute of Metrology (China), provincial metrology institutes and related flow enterprises, focusing on the domestic typical large diameter water flow standard facility has been built to carry out the investigation and research, comparative analysis of different types of device structure principle, measuring ability, technical characteristics and the regional distribution, etc. Based on this, the key technologies that may emerge in the field of large diameter water facility in the future are explored and the future development trend is summarized. The relevant research results of this paper have important practical significance for improving the measuring capacity of domestic large water flow facilities, standardizing and improving the construction of traceability system for large water flow measurement.

Liu xun, Luo Caiping , Liu Renhuai
Research on intelligent ultrasonic gas meter based on Lora communication technology

The existing membrane gas meter has the disadvantages of low measurement accuracy and difficult to realize remote monitoring. The new ultrasonic gas meter can solve these problems after adopting the new Lora communication technology. This paper describes the measurement principle of the ultrasonic gas meter and the components of the ultrasonic gas meter. The hardware composition block diagram of the gas meter and the design idea of low power consumption are described. The software design framework and main design flow chart of the gas meter are described. The detailed design of segment code liquid crystal is described. The design of Lora communication module is also described in detail. The flow measurement accuracy of the gas meter in the flow range of 0.16 m³ / H ~ 6 m³ / h and the temperature adaptive flow measurement accuracy in the temperature range of - 10 °C ~ + 40 °C meet the measurement accuracy requirements of national standards, In the actual application scenario, the communication distance and communication performance of the gas meter also meet the requirements of customers. In the actual application scenario, the communication distance and communication performance of the gas meter also meet the requirements of customers. The gas meter has been used in many gas companies for a long time and in large quantities, and the results meet the use requirements. Finally, the conclusion is given and it is pointed out that the gas has reached our expected goal.

M. D. Schakel, F. Gugole, D. Standiford, J. Kutin, G. Bobovnik, N. Mole, R. Maury, D. Schumann, R. Kramer, C. Guenz , H.-B. Böckler, O. Büker
Establish traceability for liquefied hydrogen flow measurements

The EU aims to be climate-neutral by 2050 and usage of liquid hydrogen (LH2) for transportation is expected to grow fast. With the expected uptake, traceability in custody transfer is required. Existing metrological infrastructure can be used to provide traceability with basic calibrations performed typically under ambient conditions. However, due to the very challenging LH2 process conditions, with temperatures as low as 20 K, there is a need to determine the flow measurement uncertainty at these process conditions. Within the Joint Research Project (JRP) 20IND11 “Metrology infrastructure for high-pressure gas and liquified hydrogen flows” (MetHyInfra) [1], traceability for liquefied hydrogen flow measurements is developed by a three-pronged approach: (I) assessment of transferability of water and LNG calibrations to LH2 conditions; (II) cryogenic Laser Doppler Velocimetry (LDV) adapted to LH2 flow applications; (III) assessment of transferability of water, liquefied nitrogen, and liquefied helium calibrations in the vaporisation method to LH2 conditions. In this paper the initial MetHyInfra project results are presented comprising: (I) description of LH2 flow meters, water and LNG calibration results, analytical model prediction statements of uncertainty at LH2 conditions when calibration is performed under ambient conditions, finite element numerical modelling analysis of various thermal effects affecting CFMs at LH2 conditions, (II) design modifications of cryogenic LDV to ensure operability at LH2 conditions, (III) description of the vaporisation standard. It was found that obtaining a definite quantitative number of liquefied hydrogen flow measurement uncertainty from the analytical model is challenging for a variety of reasons.

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