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Page 177 of 977 Results 1761 - 1770 of 9762

J. Mata, L. Martins, A. Tavares de Castro, A. S. Ribeiro
Statistical quality control method for automated water flow measurements in concrete dam foundation drainage systems

Seepage through the foundation is a relevant condition for the structural assessment of concrete dams. The knowledge of the water flow measured in the drainage system installed to reduce the uplift pressure in a dam's foundation is, therefore, a main issue in the safety control of concrete dams. Monitoring systems include measuring devices to determine the water collected from drains and weirs in order to evaluate the amount of water that flows through the dam. In most large concrete dams, both manual and automated water flow measurements are possible.
This paper proposes a statistical quality control method for automatic measuring systems based on simultaneous manual water flow measurements and the knowledge of the corresponding measurement uncertainties. Experimental tests performed in a weir of a Portuguese concrete dam are described and paired water flow estimates and corresponding measurement uncertainties are presented and applied to the proposed method. The results of this study show that the method allows statistical quality control of automated water flow measurement systems applied in concrete dam drainage systems.

E Sanford, K Igarashi, R Steven
A Hybrid Wet Gas Meter Design for Marginal Fields

Combining different metering physical principles into one metering system offers various advantages. In this paper the advantages of producing a hybrid vortex and cone DP meter system is discussed. In single phase flow applications this hybrid meter produces a mass flow, volume flow, and fluid density predictions. In saturated steam and wet natural gas flow applications this hybrid meter can predict the two-phase flow quality, and total mass flow rate. The cone meter sub-system can also run the generic DP meter pressure field analysis diagnostic system ‘Prognosis‘.

R Steven, K Lewis
Orifice Meter Diagnostics – Predicting the Magnitudes of Flow Prediction Biases

With most modern flow meters there is a drive to equip the meter with a comprehensive verification system driven by a diagnostic suite. A diagnostic suite is a collection of different individual diagnostic checks grouped together to collectively offer more information. The state of the art is to use these diagnostic suites to show if the meter has a problem, and if so then use diagnostic suite pattern recognition to try to identify the source of the problem. However, there is virtually no R&D published that goes on to then try and predict the associated flow prediction bias induced by that identified malfunction. One such orifice meter diagnostic suite (commonly called ‘Prognosis’) is based on pressure field analysis. In this paper the development of Prognosis to show a problem exists, identify the source of the problem, and then predict the associated flow prediction bias is discussed.

E. Batista, M. Condeço, A. Almeida, J. Alves e Sousa, I.l Godinho
Performance study in fuel dispensers in the field of volume measurements

Like any type of measuring instruments used for commercial transactions, fuel dispensers, commonly known as petrol pumps, are submitted to metrological control in order to assure consumer protection and provide society in general and citizens in particular the guarantee of accurate measurements, the verification being directly linked with the volume measurement of the delivered fuel.
In Portugal, the fuel dispenser approved under the MID is subject to metrological control in service taking into account its annual verification by the verification bodies, following the procedures defined by IPQ, according to specific national regulations.
Presently there are 45 000 hoses of the fuel dispensers in Portugal, verified by several verification bodies equally distributed in the national territory.
In order to evaluate the influence factors in volume error determination of fuel dispensers, a study using standard test measures of different type, materials and volume was designed and implemented. The uncertainty of the volume determination according to the GUM methodology was evaluated, considering different atmospheric conditions, volume variation over time, different fuel types and determination of error the in different types of standard test measures.
There was some difference in performance and error determination when using different standard test measures, but in all implemented tests, the maximum permissible error was not exceeded. The results allowed simplifying the internal procedure while maintaining the accuracy of results.

XING Jing-fang, LIU Chen-kui, CHEN Shi-yan, NIU Li-na, ZHANG Dapeng
Model Study on the volume value of the gas discharged by high precision bell prover

This paper is based on the 0.1 class 2000L standard bell prover of gas flow which is the provincial highest measurement standard established by our institute. The research subject of this device is from the provincial science and technology special project of hebei province. In this paper, the concept of volume coefficient is proposed for bell provers with different accuracy levels.The common mathematical model is analyzed and a new Fourier fitting mathematical model is proposed. The mathematical model of the inner volume of the bell prover is given by the definite integral principle. The actual volume value of the gas discharged from the bell prover is derived by analyzing the starting and stopping process of the bell. That is the volume of the bell corresponding to the distance translated downward by the height of the bell falling which is measured by the displacement measuring mechanism. It is pointed out that in calibrating high accuracy grade bell prover, the effective use segment and its lower volume segment should be calibrated as well.

José Dias, Luís Matias, Maria Henriques
Deformations and volume changes due to moisture variations in heritage buildings - Use of NDT techniques

Elements of building envelope, during service life, are subjected to deformations and volume changes due to moisture variations, which can cause anomalies in the building, such as the cracking of facade walls and consequent rain penetration, with increase of their moisture content. In case of heritage buildings with structural concrete elements and infill masonry walls, when, besides moisture variations, other different causes can be hypothetically possible, it can be justifiable to investigate more profoundly the anomalies with the available NDT techniques. This study is related to the application of non-destructive testing (NDT) techniques, with a view to the evaluation of anomalies related to the presence and flow of moisture in masonry walls, notably through Ultrasound, Infrared Thermography (IRT) and Photogrammetry. These NDT techniques are used in the evaluation of masonry specimen with variable moisture content, subjected to compression test, before and after been tested, when cracking will be present.

H. Guta, S. Fischer, D. Dufour, M. Burckbuchler, G. Fromant
Turbulence Measurements With A New Two Components Ultrasonic Profiler

In the present paper, a data set of time-resolved two components velocity profile measurements under steady uniform turbulent rough clear water and sheet-flow are presented. The purpose of this campaign was to evaluate the performances of a commercial ADVP, the UB-Lab 2C from the company Ubertone, by comparing it to a well-established instrument, the ACVP, developed by the LEGI. This measurement method provides quasi-instantaneous co-located two (2C) components velocity profiles, overcoming limitations of previously developed acoustic measurement methods, and allowing to resolve fine flow scale for the characterisation of turbulence statistics and turbulent processes.
Taking into account flow condition differences in the tilting flume with sediment pit, the results of this measurement campaign demonstrates the good performance of the commercial ADVP compared to the ACVP, in clear water and sheet-flow. Its capabilities for time-resolved turbulence measurements are also supported by similar results described in the literature, namely, the significant reduction of Von Karman parameter in sediment-laden flows and the higher contributions of ejections in CW (and sweeps in SF) for the Reynolds shear stress. This suggests the potential of this acoustic system to analyse a wide range of hydrodynamic phenomena, both in rigid-bed and mobile-bed, in which turbulence plays a major role.

K.-H. Cheong, R. Doihara, N. Furuichi, T. Shimada, Y. Terao
Primary standard for liquid hydrocarbon at low flow rates using light oil, kerosene and industrial gasoline

Motivated by the need to establish a measurement traceability in engine fuel consumption for the industry (automobile, shipping and aviation) as well as in the household fuel metering and bio-fuel production (bio-fuel blending), NMIJ developed a primary standard for low liquid hydrocarbon flow rates that works on three common types of liquid fuels, namely light oil (diesel), kerosene and industrial gasoline (flash point over 40 °C). To achieve a high calibration accuracy below 0.1 % which is needed by the industry, this primary standard adopted the gravimetric method performing static weighing with flying-start-and-finish as the calibration method. To cater to a wide flow range from 0.02 L/h to 100 L/h, the calibration facility operates on two gravimetric systems, one using a compactly designed conical rotating double-wing diverter for 1 L/h to 100 L/h and another using a pair of high-speed switching valves as a diverter for 0.02 L/h to 1 L/h. Features of each gravimetric system and its performance are highlighted in the paper. For validation of the calibration capability of the primary standard, uncertainty analysis as well as intra-comparisons with other facilities at NMIJ are also reported.

R. Doihara, K. H. Cheong, T. Shimada, N. Furuichi
Development of small weighing system for liquid microflow

A prototype small weighing system for liquid micro-flow from 10 mL/min down to 1 μL/min has been constructed. The calibration method was the static weighing with standing start and stop. The weighing system was set in a constant temperature and humidity chamber. At small flow rates, evaporation effect comes to be a significant error source. In order to reduce evaporation error, a detachable system between a weighing tank and a pipe line has been developed. The detachable device prevents pipeline tension to the weighing scale and is able to keep the pipeline closed while collection. Performance of the weighing system was evaluated by analysis of calibration factors to a syringe pump. At a preliminary test, the collected liquid was from 0.2 g to 2 g of water. In the preliminary test, the evaporation error was estimated to be below 0.1 % down to 2 μL/min of water. The system is aiming to use at calibrations of liquid micro-flow meter for the semiconductor industry and the medical field.

Jingqiong Zhang, Tao Wang, Jinyu Liu, Yong Yan, Edward Jukes
Structural condition monitoring of Coriolis flowmeters through stiffness measurement

Condition monitoring of an abrasive or erosive process is essential to give early warning of potential issues and ensure safe delivery of fluid material via pipeline transportation. As one of the solutions to direct mass flow measurement, Coriolis flowmeters provide highly accurate and repeatable measurements in single phase flow processes. In some multiphase flow processes containing solid particles, Coriolis flowmeters may not perform well or even fail due to erosive wear of the measuring tubes. This paper presents an in-situ technique to monitor the structural conditions of a Coriolis flowmeter by analyzing a stiffness related diagnostic parameter in order to validate measurements or prevent flowmeter failure.
This paper demonstrates the procedure to extract the stiffness related diagnostic parameter from a Coriolis flowmeter, on the basis of a mathematical model of the Coriolis oscillation system. With the aid of additional frequencies applied to the drive signal, the stiffness related diagnostic parameter of the measuring tubes is determined through frequency response analysis. This stiffness diagnostic parameter is linked to the physical stiffness of the measuring tubes by introducing a scaling factor. Furthermore, various vibration models, with different degrees of freedom and damping levels, are used to simulate the stiffness diagnostics in Coriolis flowmeters. The feasibility and repeatability of the proposed method are verified through computer simulation and experimental tests. The results show that the proposed method performs well in determining the stiffness related diagnostic parameter of a Coriolis flowmeter and hence the verification of its structural condition.

Page 177 of 977 Results 1761 - 1770 of 9762