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Page 47 of 939 Results 461 - 470 of 9382

Yumin ZHAO,Xin LI, Yingwei DOU, Chao ZHANG, Xinqiang MA
Research on different test methods based on heat meter flow sensor

Heat meters as an important measurement instrument and the basis for heatingbilling purpose, must ensure the accuracy and long-term reliability of measurement.After the heat meters from domestic brands are installed in the field, quality issues are frequently happening. Due to this reason some of the market is replaced by the heat meters from imported brands. Reflected to the test method, there is a big difference and one of the biggest differences between European and Chinese product standard on the durability requirement. This researchaims to establish a study based on a testing of 4,000 times temperature alternation, to make comparison to the 2,400 hours testing and to have a continuous perfection on durability requirement from standard perspective.It’s the first time in China to have an overall assessment towards the durability of heat meter in the condition of laboratory. This would provide theoretical support to the transformation and upgrading of the heat meter industry,and empower the development of heating billing.

De-fu Xu, Jun-Mu, Shun-li Wang, Dun-li Liu
Experimental and Simulation Research of Channel Flowmeter Based on Gas and Water

The measurement performance of the channel flowmeter is studied by meansof numerical simulation and experimental verification. The variation trend of the outflow coefficient and differential pressure value of the channel flow rate with the flow velocity under the gas-liquid two media is obtained, and the measurement error under the gas-water and liquid-phase conditions is analyzed. The results of numerical simulation are compared and analyzed. Research shows that there is a stable region of outflow coefficient in both gas phase and water phase experiment conditions. As the Reynolds number increases, the outflow coefficient tends to be a constant and does not change. In the stable outflow coefficient region, the difference of the upper limit value of Reynolds number is smaller than the difference of the lower limit value of Reynolds number. In the stable region of the outflow coefficient, the difference of the average outflow coefficients of the gas and liquid phases is not significant. In addition, the gas phase test shows that the critical back pressure ratio has a great influence on the outflow coefficient outside thestable outflow coefficient region, and the effect is not significant in the stable outflowcoefficient region.

Mingchang Guo,Chi Wang, Hongwei Zheng, Chuanbo Zheng
Discussion on the Application of Measurement Reproducibility in Gas Flow Standard Devices by Master Meter Method

Based on the analysis of the test results of several gas flow standard devices by master meter method, it is found that under the same flowing conditions, the indication errors of a meter under test at the same flow rate with different master meters in a set of standard device are not consistent with each other, the deviations are 0.08 % ~ 0.21 %, that is, there will be a non-negligible systematic deviation in the results of the verification or calibration of the flow meter with different master meters. In the present paper, the reproducibility of test results is innovatively introduced to measure the consistency of measurement results of different master meters in a gas flow standard device, and the reproducibility application in the performance examination, uncertainty evaluation and quantity transfer of a gas flow standard device is discussed.

Ming Gao, Zhancheng Bu, Hu Zhang
Research and Application of On-Line Measurement of Liquid Point Velocity in Closed Circular Tube

In our work, there are many liquid flow meters used online that cannot be sent to the laboratory for traceability, but can only be traced online on site. Due to the unsatisfactory conditions of the liquid medium in the online closed circular pipe and the existence of serious corrosion on the inner wall of the pipeline, the internal structure of the pipeline cannot be detected during the online inspection, which makes it difficult to accurately measure the liquid flow rate in the pipeline online, resulting in inaccuracy of traceability. By studying the flow characteristics and velocity distribution of the liquid in the pipeline, a device that can detect the internal conditions of the pipeline and measure the liquid online is designed. The flow velocity curve is fitted by the algorithm of measuring point interpolation, and the flow velocity deviation is corrected by using a high-precision measurement standard device. Through the integration of the infinite flow unit, the flow rate in the online state is obtained. According to the measurement needs, the measurement points are added. After fitting and correction, the measurement accuracy of the flow velocity at the inner point of the closed tube is improved.

Yixin Sun, Zhi Cao
Factors Influencing the Allocation Measurement Computation Procedure of Water-Cut Crude Oil

Water-cut crude oil has a great influence on crude oil trade measurement. The accuracy of oil volume in water-cut crude oil is closely related to the interests of both buyers and sellers. In this paper, the computation procedure based on API20.1 is analyzed in order to assure one more accurate metering method for the volume of oil. This paper uses the data from one metering skid to discuss the influence effect of different factors involved in the computation procedure. The analyzed factors include the density of crude oil/water mixture at metering conditions, volume fraction of water in the crude oil/water mixture at metering conditions, shrinkage correction factor of crude oil, and temperature at metering conditions. Analysis results show that the factors did not have an equal effect on the calculated volume of oil. The density has the least influence range on the oil volume of water-cut crude oil. The temperature is the least sensitive factor. The volume fraction and shrinkage correction factor need to pay more attention to because the calculated volume of oil is highly sensitive to these two factors.

C. Kroner, H. Warnecke, O. Büker, K. Stolt, P. Wennergren, G. Hagemann, M. Werner
Metrology for reliable fuel consumption measurements

Reliable fuel consumption measurements play an essential role in developments to increase engine efficiency and the transformation to e-fuels or emission determination. A verification of the performance of flow meters used for the fuel consumption measurements under real-world conditions compared to laboratory conditions is thus of great interest since often the measurement technology must be an order of magnitude better than the targeted improvements. Apart from the influence of the pressure- and temperature-dependent transport properties of the fuels and the ambient conditions, a characterization of the measurement performance under dynamic fuel consumption and at low or zero consumption is of particular relevance. Traceable metrological infrastructures and procedures, which will enable an evaluation of the measurement performance of flow meters in this regard, are currently being developed within the scope of the EMPIR-project “Safest” (20IND13). Test profiles based on the demand of the engine control unit were derived for passenger cars and trucks which take up characteristic sequences of the harmonized test cycles WLTC and WHTC. The profiles can simply be scaled to reflect different engine sizes. Based on a profile from a ferry navigating in a harbour the performance of flow meters used in the maritime sector is investigated. In addition to the measurement accuracy under dynamic conditions, the performance of flow meters is analysed related to ambient conditions and different transport properties of the fuels. The investigations show influencing factors that should be considered when determining emissions by means of flow measurements of the fuel supply to the engine.

Y. Xiang, M. Y. Qin, Y. F. Xing, W. H. Zhou, X. Liu
Research on flow field characteristics of flowmeter fairing based on CFD

In this paper, under complex pipeline conditions, the fluid flow field is seriously distorted, which affects the measurement accuracy of the flowmeter. As one of the main components of the flowmeter, the rectifier has an important impact on its measurement accuracy and reliability. Aiming at this problem, the simulation experiments of rectifiers with different structures are carried out in this paper. Firstly, combined with the working principle and structural composition of the turbine flowmeter, the factors affecting the measurement accuracy of the flowmeter are analyzed. Then, the structural model of the rectifier and the pipeline is established, and the flow field distribution in three cases without rectifier, with honeycomb rectifier and with arc rectifier is studied by CFD simulation.The simulation results show that compared with no rectifier, the honeycomb rectifier and the circular arc rectifier have good performance in effectively reducing eddy and turbulent flow, providing more stable and repeated velocity profiles and further improving the flow field distribution. Under the same conditions, the rectification effect of the honeycomb rectifier on the fluid flow field is more significant.This work is very useful for accurate measurement of turbine flowmeter, especially for the complex pipeline conditions.

Xiao-Zhang ZHANG
Basic errors of Coriolis flowmeters in liquid-gas two-phase flow

Liquid-Gas two-phase flow causes measurement error in Coriolis flow meters. The topic has been studied by researchers including working out mathematical models, doing real flow tests in laboratories or industry.In this paper, we study the ‘bubble model’ again, which is often referred to in two-phase flow model for Coriolis flow meters. Using the concept of Archimedes buoyant principle, we obtain a different result from Landau’s for acceleration ratio of a sphere bubble in a vibrating ideal fluid. Thus measurement error model of two-phase flow for Coriolis flow meters is re-discussed. On the other hand, data of flowrate measurement errors abstracted from a number of references are plotted. It was found that most of the data falling within a region of between, which is in agreement with the theory deduced in this paper.

Liuweijun
A calculation model of natural gas compression factor

“GBT/17747.2 Natural gas-Calculation of compression factor- Part 2 ” refers to the calculation method of “AGA8-92DC” equation, which is very accurate for the calculation of conventional natural gas compressibility factor, but in the calculation process, a large number of intermediate variables, positioning parameters and interactive parameters are introduced, which makes the calculation process more complicated. Based on the critical state of mixed gas, a new fitting formula is proposed to replace the binary interaction parameters used in “PR” equation, so as to simplify the calculation process. Compared with the original “PR” equation and “AGA8-92DC” equation, the calculation results of conventional natural gas compressibility factor and acid natural gas compressibility factor are more close to the laboratory measured compressibility factor.

W. L. Chen, C. H. Li, J. Mu
Influence of Probe Local Flow Field Distortion on Measurement Results of Ultrasonic Flowmeter

The installation of the intrusive probe will disturb the internal flow field inside the ultrasonic flowmeter, which will affect the measurement results. Probe protruded into the flow or recessed into the wall is one of the most important uncertainty sources of ultrasonic transit-time flowmeters. There are three ways to install theprobe of the ultrasonic flowmeter in the pipeline: fully convex installation (the probe protrudes into the pipeline),fully concave installation (the probe is installed to form a depression on the pipe wall) and tangent installation(the center line of the probe is flush with the pipe wall, a part of the probe protrudes from the pipe, and a depression is also formed on the pipe wall).In this paper, for the small and medium-diameter ultrasonic flowmeters with double-sided 8-channel arrangement, numerical simulations are carried out under the fully convex, fully concave and tangent probe installation modes, respectively. By analyzing the flow field distribution near the probe and the change of the velocity profile on the path line, the physical mechanism of the influence of the flow separation caused by the mainstream flow near the probe on the measurement results of the ultrasonic flowmeter is revealed. Then the influence of probe disturbance on the measurement results of ultrasonic flowmeter under different pressure and flow rate was analyzed by experiments, and the error correction model is proposed according to the experimental results. The research contents provide a theoretical basis for the installation and use of ultrasonic flowmeter.

Page 47 of 939 Results 461 - 470 of 9382