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Page 178 of 977 Results 1771 - 1780 of 9762

Miroslava Benková, František Schweitzer
New Primary Standard With Piston Prover For Microflow Of Liquids

The Czech Metrology Institute continues in development of a method in the area of very small flows of liquid aimed at reducing uncertainties and expanding flow to lower values. The primary standard developed based on mass method has successfully been internationally compared and the results have shown data stability. With increasing accuracy of flow meters on the market, requirements for reduction of uncertainty of primary or secondary standards are rising.
In case of very small flows, i.e. below 10 ml/h, some calibrations and subsequent result evaluations by means of the weighing method become a little complicated. With the aim to automate the calibration process as well as to reduce uncertainty of measurement and also enlarge the range to lower flows, an innovative primary standard with 200 mL micro piston prover has been developed. Long-term experience with development of a volumetric method using a similar type of piston prover with a special fluid displacement system in the area of the larger flows was applied.
The paper is focused on the presentation of the comparison of measurement results between the volumetric standard with the piston prover and gravimetric standard in one place. A detailed design of the new test equipment with integrated micro piston prover into the testing line is presented as well. Further, experimental measurements in very low flow rates (1 to 6,000) ml/h are described and evaluated. Achieved measurement uncertainties are also presented. The results show the benefits of the applied method.

J. Sluse
Influence of disturbing part on measurement of the standard for cryogenic flow rate measurement using LDV

Disturbing parts situated on upstream of the flowmeter have influence on inlet velocity field. This change on the inlet of the flowmeter may influence measurement accuracy of the flowmeter. The aim of this article is to determine influence of disturbing parts on the measurement. Typical disturbing part situated on upstream of the flowmeter is elbow, swirl, half-plate, valve etc. The influences will be determined the standard for cryogenic flow rate measurement using LDV which was developed for measurement of the flow rate of liquefied natural gas (LNG) and other cryogenic fluids. The measuring system is simplistically special type of Venturi tube. Principle of this system is measurement of velocity profile using laser doppler velocimeter (LDV) behind the nozzle where the velocity profile is flat. After that the flow rate is calculated from measured velocity profile and diameter of nozzle throat. The influence of disturbing part on accuracy of the measurement will be determined by using numerical simulation. The determination of rate of the influence will be carried out by comparison of numerical simulation with and without the disturbing part. The simulation will be carried out for several disturbing parts.

Y. Arellano, A. Hunt, O. Haas, H. Ahmed, L. Ma
Water cut determination in co-current liquid-liquid flow using electrical capacitance metering

Despite intensive research dedicated to multiphase flow measurement in the past decades, accuracy remains one of the key challenges in the oil and gas industry. The Multiphase flow of gas-liquid mixtures has been extensively addressed in the literature. However liquid-liquid flows, are intrinsically more complex and their hydrodynamics are not yet completely understood.
The present study investigates the capabilities of in-line tomography technologies for water cut determination in co-current immiscible liquid-liquid flows. The proposed experimental metering system operates by interrogating the imaging region contained by the pipe walls with a high-frequency alternating electric field. The experiments are conducted on the horizontal section of a flow rig of 100mm in diameter using synthetic oil and saline water as test fluids. Measurements of stratified flows from electric capacitance tomography are contrasted to measurements from an electrical capacitance meter. Measurements enable the computation of water cut in horizontal pipes for diverse flowrates. The results show for the first time the potential of using high frequency non-intrusive electric capacitance meters for oil-water flow measurement.

M. A. Silva,, D. Loureiro, A. S. Ribeiro, C. Amado
Factors influencing the quality of flow measurements in drinking water systems – lessons learned

The flow measurement is essential for drinking water network monitoring. A better knowledge about the flow that is abstracted or pumped to drinking water systems, transferred between water utilities or monitored at the entrance of the subsystems can be achieved through the flow measurement. Nevertheless, this is a topic insufficiently studied. The accuracy can be an excellent parameter to the analysis of the uncertainty sources impact on the measurements obtained from manufacturer’s catalogues, and the contributions related with installation, data acquisition, transfer, storage and processing. To understand the influence of these factors in flow data, a set of flowmeters from six water utilities was selected and surveyed in this paper. This paper aims to explore a methodology to analyse the relationship between the uncertainty in daily flow patterns and influential factors. To run the analysis, a robust coefficient of variation was computed for each hour of the workday flow pattern. The most influential factors were: the direction of the flow measurement, year of installation and practices adopted for nominal diameter selection. Although the flow profiles and the elbows are considered in the literature as factors that influence the measurement, in this set of flowmeters, no influence was verified. This exploratory analysis allowed to point out factors related to flowmeter installation that have a significant impact on the quality of the flow measurements.

S. Knotek, J. Geršl, A. Paták
Uncertainty of SO2 measurements in dryers due to water droplet and water film condensation

The article presents the modeling of SO2 diffusion into water droplet and water film which arise in dryers by condensation or evaporation in dependence on physical and chemical conditions. The motivation of the modeling is the attempt to quantify the SO2 loses in drying during sampling of emissions. The basic processes of gaseous substances dissolution into liquid are discussed theoretically and quantitative results of computer computations are presented.

Y. Liu, X. Feng, Y. Yao, L. Lei, P. Zhao, T. Meng, L. J. Huang
Calibration of Microfluidic Flow Meters

Calibration of a microfluidic meter is conventionally done with a precision reference such as a high accurate balance or a precise syringe pump system. These processes normally are very time consuming and are not the feasible approaches for high volume flow meter manufacture. In this paper, we will discuss the comparison of the calibration options of the thermal time-of-flight microfluidic meter including the precise syringe system, balance and Coriolis flow meter. The flow range of the meter covers from 20μL/min to 400mL/min. The comparison of the metrology features and the procedure of each system is discussed. Further, for the hygienic sensitive applications, the liquid calibration often leads to concerns for the cleaning procedure after the calibration. Comparison of the calibration with the calculated values and DI water and the conversion between the fluids is also discussed.

Heming Hu, Yuan Liu, Zhigang Wang, Zeyu Guo, Yunlong Zhu
Design and Performance of Water Flow Velocity Calibration Facility

Current meters are used for flow velocity measurement in river and ocean. Accurate measurements need accurate calibrations. There are more than ten tow tank facility in China providing water velocity calibration, and all of them are ~ 100 m long concrete tank with no clear uncertainty budget, especially there is not a thorough understanding of the water movements in the tow tank. We have built a small tow tank which is 8 m long, 1.2 m wide and 1.2 m high with a cart running speed of 0.01m/s ~ 1m/s. It was made of transparent glass and was possible to use optical instruments to investigate the background flow filed that might compromise calibration results. In order to test the performance of flow velocity calibration facility, Micro ADV produced by Sontek was employed to make a test, and the results showed that the calibrated results for ADV using flow velocity calibration facility proposed in this article agreed well with the manufacture’s declaration for accuracy and USGS’s conclusions. In addition, SNR (signal-noise ratio) of MicroADV was also analysed and related to the concentration of particles in water body. The performances verified that the flow velocity calibration facility was effective and could be used to conduct further analysis of current meters.

B. W. Sims, J. A. Brandt, R. J. McKee
A Low Reynolds Number Discharge Coefficient Equation for Critical Flow Venturis and the Effects of Inlet Radius

The discharge coefficient, Cd, for a Critical Flow Venturi Nozzle (CFVN) corrects the theoretical mass flow to the actual mass flow at measured inlet conditions. The theoretical mass flow is calculated using 1-D isentropic theory and does not account for the subsonic boundary layer along the CFVN wall. For a precisely known throat area, Cd must be less than unity due to this boundary layer. Theory predicts that the geometry of the inlet to a CFVN will affect the boundary layer and therefore effect the Cd. This effect on Cd becomes more significant for smaller CFVNs which are operated at lower Reynolds Numbers. The international standard, ISO 9300 [1], for toroidal CFVNs allows inlet curvature to vary from 1.8 to 2.2 times the throat diameter, d, but limits the use of the Empirical Cd-Reynolds Number equation to Reynolds Numbers above 21000. Low Reynold’s Number calibration data for hundreds of small CFVNs with 2d inlet curvature will be used to generate an Empirical Cd- Reynolds Number equation. This paper will also present the results of testing multiple CFVNs with varying inlet curvature at low Reynolds Numbers. These results will be used to examine the specific Cd sensitivity to this geometric component and determine if more stringent inlet curvature requirements are necessary for low Reynolds number CFVN applications. The Empirical Cd-Reynolds Number equation, along with additional inlet curvature guidelines will be presented as a method for calculating actual mass flow through a CFVN when the Reynolds Number is below the minimum value at which the ISO 9300 [1] equation can be applied.

D. van Putten, L. H. van Luijk, H. J.Riezebos, B.Tinge
Assessment of allocation systems: combining Data Validation & Reconciliation scheme and PVT simulations

For increasingly complex production systems, the traditional allocation processes appear to be less suitable and an alternative methodology is required. An assessment was carried out on a large wet gas allocation system containing more than 120 wells. The assessment was based on an approach that combines the Data Validation and Reconciliation (DVR) methodology and process simulations to accurately calculate the reconciliation factors applied to each well. It was found that the current imbalance and the allocation method complies with requirements stated in the agreement between stakeholders. The assessment provided much insight in the sensitivity of the overall gas balance and provides prioritization of the improvements to minimize the imbalance. A more balanced allocation system leads to a fairer division of the accrued revenues.

E. M. Graham, M. Reader-Harris, G. Chinello, K. Harkins, N. Bowman, L. Wales
Vertically installed Venturi tubes for wet-gas flow measurement: possible improvements to ISO/TR 11583 to extend its range of applicability

Venturi tubes are commonly used for wet-gas flow measurement, and the majority of commercial wet-gas flow meters generally include a Venturi tube installed vertically with embedded secondary instrumentation. The presence of the liquid causes an increase in the measured differential pressure and results in the Venturi tube over-reading the actual amount of gas passing through the meter. Most of the research in the literature is focused on the investigation of the over-reading for horizontally oriented Venturi tubes, thus limiting the development of over-reading correlations for vertical installation. An experimental campaign was recently conducted at the National Engineering Laboratory (NEL) high-pressure wet-gas loop, where three Venturi tubes of the same nominal diameter (4”) but different throat to inlet diameter ratio (0.4, 0.6, 0.75) were tested, installed vertically after a blind tee. The results of this experimental campaign are presented in this paper and the effects of various parameters (line pressure, gas Froude number, diameter ratio) on the over-reading are briefly discussed. It is shown that the over-reading correlation included in the ISO/TR 11583:2012 and developed for horizontally oriented Venturis, is not applicable to vertically oriented Venturis. However, if modified, the correlation included in the ISO/TR 11583 is capable of meeting its stated uncertainty limits for the experimental data presented here for vertically installed Venturis.

Page 178 of 977 Results 1771 - 1780 of 9762