Measurement Library

North Sea Flow Measurement Workshop Publications (1999)

Multiphase Flow Measurement System Of High-Gor Applications
Author(s): Harry Cellos
Abstract/Introduction:
This paper presents the findings from an installation at Prudhoe Bay which was started up on October 22, 1998. This system consists of a MFI Multiphase Meter, a partial separation separator and a coriolis effect flow meter. The separator is used to widen the operating envelope of the multiphase meter. The control of the separator, data acquisition and final calculations are done by the MFI Meter. Since the system has a very wide operating envelope it can be used on groups of wells with widely divergent flow rates. This particular system is designed for accurate flow measurements with GORs up to 80 000 scf/bbl and it can handle liquid flow rates in the range 100-15 000 bbl/d. The accuracy of the oil flowrate is typical within 5% and the gas flow rate is measured within 2-3%. The key element of the system is the MFI multiphase flow meter which is used to measure the multiphase flow in the liquid leg of the compact separator. Unlike most well test systems, the measurements of the liquid line are not adversely affected by gas carry under. In fact, it works best with gas flowing in the liquid line. Operation and control of the system is greatly simplified by the fact that the primary goal of the separator is to remove the liquid from the gas. The separator is designed to remove down to 5 ppm over the full range of flow rates. The excitation voltage of the coriolis meter is used to detect carryover down to 2-3 ppm. This variable is also used in the control logic and changes the vapor leg flow rate to eliminate carryover.
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Document ID: EF0BEBE0

Proving A Fiscal 5-PATH Ultrasonic Liquid Meter With A Small Volume Ball Prover. Can It Be Done?
Author(s): Trond Folkestad
Abstract/Introduction:
Norsk Hydro is installing its first fiscal liquid metering station based on Ultrasonic meters on the Oseberg Sr (South) platform comprising two multi-path Ultrasonic liquid flow meters in series with an Unidirectional small volume ball prover. The Ultrasonic liquid flow meters are 8 Krohne 5-path Altsonic V meters while the 12 Unidirectional ball prover is a Kongsberg Offshore design. During flow testing of the metering system the required repeatability during proving could not be achieved. The repeatability during proving varied between more than ten times the requirement in the regulation from the Norwegian Petroleum Directorate (NPD) to just within the requirement. Most of the time varying between three to six times the requirement. This paper will share the experience gained during flow testing the metering system for four months in Brevik, Norway. The paper will conclude with a recommendation for better test set-up and system design when using this type of Ultrasonic liquid flow meters with a small volume ball prover.
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Document ID: 8298087F

New Generation Multiphase Flowmeters From Schlumberger And Framo Engineering As
Author(s): I.Atkinson, m. Berard, B-V Hanssen, G. Segeral
Abstract/Introduction:
The cooperation between Schlumberger and Framo Engineering has resulted in a significant step forward in multiphase flow metering. This paper describes a new instrument, called VenturiX, which will be implemented in two new products: PhaseTester, dedicated to Periodic Testing services, and PhaseWatcher, dedicated to Permanent Monitoring applications. The VenturiX is a compact instrument consisting of a venturi and a dual energy composition meter located at the Venturi throat and interrogated at high rate. The meter response is flow regime independent so no upstream flow conditioning is needed. It has been extensively tested over the last three years in several flow loops and in real field conditions. The results of these tests are reviewed.
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Document ID: 3E032C3E

A HIGH-ACCURACY,CALIBRATION-FREE Multiphase Meter
Author(s): G.J. Miller, W. Letton, A.M. Scheers
Abstract/Introduction:
The need for accurate and reliable measurement of three-phase flow streams is well documented. To this end Daniel have developed a high-accuracy multiphase flowmeter MEGRA based on the sound measurement principle of (multiple energy) gamma ray absorption. The ultimate aim of such technology is to replace the measurement function of the traditional test separator with a cheaper, lower-maintenance and calibration-free alternative. At present, due to its high-accuracy water-cut (WC) and real-time performance, MEGRA has also been utilised for well management programs downstream of traditional test separators. The flow-rates of the individual water, oil and gas phases are derived from a measurement of the bulk flow through an annular Venturi, combined with phase fraction information deduced from the absorption of gamma-rays within the multiphase fluid. The gamma-ray technique has the advantage over other multiphase metering methods in that it is applicable over the full range of water-cuts from 0 - 100% and does not depend upon the nature of the emulsion present. This paper outlines the basic principles behind the multiphase flow measurement and highlights some of the advantages of the present technology. The use of relatively low-energy gamma-ray emissions and high-resolution solid-state detectors lends an enhanced sensitivity to the measurement. Consequently, water-cuts and gas volume fractions can be determined to high accuracy ( 2%) in relatively short measurement times ( seconds).
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Document ID: 51E249B8

Compact Cyclone Multiphase Meter Ccm() Discussion Of Metering Principle, Slug Handling Capacities And Flow Measurement Results
Author(s): Arne Myrvang Gulbraar
Abstract/Introduction:
This paper presents the Compact Cyclone Multiphase (CCM) meter - the metering principle, slug handling capacities and flow measurement results. The CCM meter has previoiusly been presented in various papers /1/-/4/. It is a separation type multiphase meter utilising cyclonic separation technology for compact separation of gas and liquid. After the gas/liquid separation, gas and liquid is measured individually by conventional single phase instruments before the phases are re-mixed for further multiphase transport.
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Document ID: 1C957A32

The Effects Of Salinity Variation On Dual Energy Multiphase Flow Measurements And Mixmeter Homogeniser Performance In High Gas And High Viscosity Operation
Author(s): P. Harrison, S.J. Parry, G.L. Shires
Abstract/Introduction:
It is a continuing concern of those involved with multiphase flow meters using dual energy X-ray/gamma phase fraction measurement that changes in the properties of the fluids being measured will cause errors. Density changes are accommodated through known PVT relations but changes in the chemical composition of the flowing fluids must be corrected for if errors are to be avoided. While significant changes in overall hydrocarbon composition are not usually encountered, salinity of the water fraction can vary over time for some wells and this changes not only the physical density but also the mass absorption of the water. In the first part of this paper the effects of fluid property changes on dual energy measurements are discussed in relation to the energy levels most commonly used for measurement. The second part of the paper presents recent results from the Mixmeter homogeniser which continues to demonstrate excellent characteristics as a differential pressure meter in multiphase flow. Data for high gas fraction operation is presented together with work using high viscosity emulsions.
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Document ID: 79D3E030

Water-In-Liquid Probe System For Measuring Water-In-Liquid Ratio At Low And High Gas Volume Fractions
Author(s): Christian Dreyer Skre
Abstract/Introduction:
Aprototype dielectric on-line monitor for measurement of water cut in multiphase petroleum flow has been built. The system is a low cost and robust system capable of measuring 0-100% water cut at 3% uncertainty. The system has been tested successfully at gas volume fractions (GVF) ranging from 0% to 93%. The monitor is designed with a view to installation topside, subsea or downhole. The measurement concept is based on dielectric measurements of the liquid in the flow at high frequency using an open ended coaxial probe. The method utilises the complex permittivity of the fluid to calculate the water cut. The instrument consists of the dielectric sensor installed in the pipe wall, an electronic unit for measuring the complex reflection coefficient and a PC for control, signal analysis, calculation of water cut and data presentation. The sensor facilitates easy installation, e.g. similar to a pressure transducer.
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Document ID: F8AA177F

Functional Enhancements Within Ultrasonic Gas Flow Measurement
Author(s): Per Lunde, Kjell-Eivind Frysa, John Bjrn Fossdal, Tom Heistad
Abstract/Introduction:
Results and progress from an ongoing R&D program related to the Kongsberg Metering MPU 1200 multipath ultrasonic gas flow meter are presented. The results are outcomes of an R&D Joint Industry Programme (JIP) conducted by Kongsberg Metering (KOS) in a cooperation with Christian Michelsen Research AS (CMR), Statoil, Norsk Hydro and Phillips Petroleum Company Norway, and supported by the Research Council of Norway. The JIP addresses three main topics: (1) calculation of gas density from the measured sound velocity, (2) operation at complex installation conditions (with disturbed flow velocity profiles), and (3) measurement of wet gas.
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Document ID: 6941D9FE

Investigations Regarding Installation Effects For Small Ultrasonic Gas Flow Metering Packages
Author(s): Geeuwke De Boer, Martin Kurth
Abstract/Introduction:
Ultrasonic gas flow meters for custody transfer measurement (accuracy better than 0.5%) have gained a rapid and increasing acceptance over the last few years. The most common applications are gas transmission and underground gas storage (UGS), due to the typical benefits of ultrasonic flow meters, such as no pressure drop, large turn down ratio and the bi-directional capability. Generally, this used to concentrate on the larger sized meters and installations (typically 10 and higher). An important contribution for the acceptance was the research regarding installation effects, which as a consequence, had mainly been focussed on larger sized meters. Based on trade-offs between the purchase price of an ultrasonic meter, operating costs, and total capital expenditure for a gas flow metering installation, it is anticipated that in the near future ultrasonic gas flow meters will also become a viable alternative for an increasing number of applications in smaller sized systems. The market has shown a specific interest in a package consisting of an ultrasonic meter and a flow conditioner. Also when a back-up meter or check meter is required a combination of an ultrasonic meter and a turbine meter would be an economical solution. Therefore it was considered to be of interest to initiate a research project dedicated to installation effects and the effects of various flow conditioners, for a smaller size ultrasonic gas flow meter (6), in particular in a package including a flow conditioner or a turbine meter. Results will be presented of a series of tests with different upstream conditions, performed at the HDV Lintorf test facility owned by Ruhrgas AG. Due to the fact that not all tests have been finished at the time of writing of this paper, the results are not yet complete and only the first sets of results will be presented in this paper. As typical applications for smaller sized meters are found in stations measuring the gas flow from a high pressure transmission line to a lower pressure distribution network or to a large industrial consumer, solutions are suggested to avoid the potential ultrasonic noise problem due to pressure reduction by means of optimising station design for use of an ultrasonic gas flow meter.
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Document ID: D1B2A722

Aspects Of Bi-Directional Fiscal Metering By Means Of Ultrasonic Meters
Author(s): G.H. Sloet
Abstract/Introduction:
N.V. Nederlandse Gasunie is the major gas transmission company in the Netherlands. In 1998 the company sold 79.8 billion m3 natural gas. From this amount of gas 43.4 billion m3 was sold in the domestic market and 36.4 billion m3 was exported to other European co untries. To deliver the gas to its customers Gasunie operates an extensive gas transmission grid, with 11389 kilometres of transmission lines, 8 compressor stations, 75 regulator stations, 15 export stations and 1114 city gate stations in the domestic market. Starting in 2001, Russian gas will flow via Poland and Germany to the Netherlands. The gas will enter the Dutch transmission system at the existing Oude Statenzijl export station in the northern part of the country. Importing gas via a station that has been designed as an export station is a new phenomenon for Gasunie and a redesign of the existing station is necessary. Gasunie Research was approached with the instruction to work out and test a proposal for a bi-directional flow measurement concept based on ultrasonic gas meters. In this paper an overview of the work executed so far will be presented, together with results of experimental work that has been done at Gasunies high pressure, high flow Bernoulli laboratory at Westerbork, the Netherlands.
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Document ID: F95F74B0

How To Optimise Allocation Systems By Using Monte-Carlo Simulation
Author(s): L. Coughlan, m. Basil, P. Cox
Abstract/Introduction:
The present low Oil price is forcing all petrochemical operating companies to actively review and reduce expenditure whilst maintaining or increasing production, ensuring a healthy return on investment for the shareholders. This has generated the need for new and innovative approaches in the way we manage our business. By forming a common interest group between operating service companies ideas can be developed with more focus and put into practice quicker. The authors having formed such an alliance would like to demonstrate that, by application of system models utilising Monte Carlo Simulation (MCS), how the operator can focus his limited resources and budget in the areas of greatest sensitivity and where the biggest benefit can be gained.
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Document ID: ABBA5715

Turnkey Well Testing Services: A Successful Modality Measurement In Mexico
Author(s): Noel E. Santamaria
Abstract/Introduction:
As part of the program to modernize the surface production facilities, many oil companies have implemented the use of new technologies such as the multiphase flow measurement systems among others. These technological advancements have allowed companies to automate and simplify the operations required to measure flow in oil wells. In most cases, the implementation of this technology has been achieved by acquisition of the necessary equipment and in some cases through leasing. However, in Mexico after throughout studies had proven its feasibility, it was decided to apply a totally new concept for an specific application. It consists in contracting an integrated well measurement service directly from a company equipped and qualified to provide it efficiently. The company then follows a measurement activity program prepared by Pemex Exploration and Production.
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Document ID: 11D4E6BC

Presentation Of The Handbook Of Uncertainty Calculations - Fiscal Metering Stations
Author(s): Eivind O. Dahl, Ronny Albrechtsen
Abstract/Introduction:
A new Handbook 1 for uncertainty calculations on fiscal metering stations is presented. The Handbook has been developed by Christian Michelsen Research AS (CMR) on behalf of the Norwegian Society for Oil and Gas Measurement (NFOGM) and the Norwegian Petroleum Directorate (NPD). The aim of the Handbook is to secure a more uniform uncertainty evaluation of fiscal metering stations. The Handbook provides a practical introduction to uncertainty calculations based on the principles and terminology defined by the ISO-publication Guide to the expression of uncertainty in measurement 2. Furthermore, the Handbook contains a comprehensive evaluation of two specific fiscal oil and gas metering stations. The uncertainty calculations are implemented in two software programs that are described and included as a part of the Handbook.
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Document ID: AFAA102D

Square Root Error And Impulse Line Pulsation At Cats. Terminal MIDDLESBROUGH,UK
Author(s): Mike Donoghue, Martin Crane
Abstract/Introduction:
The Central Area Transmission System (CATS) is a natural gas gathering system based in the central area of the North Sea. A riser platform and 255 miles of pipeline, including six subsea tie-in points, supplies gas to the Teesside based terminal that is situated on the North East coast of the United Kingdom. BP Amoco operates the system on behalf of CATS coventurers which consists of the following companies BG International, BP Amoco, Amerada Hess, Phillips, TotalFina, and Agip
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Document ID: 9E2D56BE

Multiphase Measurement System With Fully Redundant Measurements To Improve Accuracy And Simplify Maintenance
Author(s): Arnstein Wee
Abstract/Introduction:
Multiphase flow meters have been accepted and used by the industry for reservoir management and production allocation for several years. Multiphase metering is a fairly new technology that is an attractive alternative to test separators due to reduced field development and maintenance costs in addition to real time information as opposed to long term averages. However, multiphase metering technology is not yet very well understood by all fieldoperators, which makes it more challenging to verify correct operation and further to detect and isolate failures compared to conventional test separators. Traditionally, three phase measurements has been performed by separating the flow and measuring at single-phase conditions. Single-phase measurements are well understood by the industry and although the measurement uncertainties of a test separator in many cases are underestimated due to the operational limitations and maintenance requirements, operators normally have procedures and skilled personnel to ensure reliable measurements. Multiphase measurement differs from a traditional single-phase measurement system by simultaneously performing multiple measurements to measure multiple flow rates. Since the final results are based on a combination of several measurements, any error in just one of the measurements may affect one, several or all the derived flow rates. This aspect of multiphase metering adds to the complexity of deriving simple procedures for maintenance and proving of a multiphase flow meter. Consequently, operators are reluctant to remove the test separator as a proving mechanism to fully take advantage of the cost benefit by using multiphase flow meter. This paper describes a system that can justify omitting the test separator as a proving mechanism by adding two independent and redundant systems to a standard MFI MultiPhase Meter. The system is an integrated part of the MFI MultiPhase Management System (MMS) and enables operators to extend savings in investment and operating expenditures gained from multiphase metering technology.
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Document ID: 7C71BD3B

Operational Experience With Multiphase Meters At Vigdis
Author(s): Odd-Petter Kalsaas, Fluenta As, Espen Egner
Abstract/Introduction:
Two identical 8 MPFM 1900 VI were delivered to the Vigdis Field Dev. project in January 1996. The meters are installed on the Snorre platform, one on each of the main flow lines from the Vigdis satellites, and were commissioned for use in October 1997. Based on an unexpected shift in the calibration of the capacitance sensor, observed and corrected during commissioning, Fluenta recommended to Saga Petroleum that the two meters should be upgraded from ceramic liners to the new PEEK open electrode construction. Saga agreed to this recommendation, and the job was performed during a two week planned shutdown in May 1998. The two multiphase meters were re-commissioned in first week of June 98. Further adjustments were done during the next months, in order to optimise the performance of the meters. MPFM measurements during a multirate test from all Vigdis wells are compared to test separator measurements in April 1999. Comparison between the multiphase meters, and the downstream separator measurements, now shows stabile and repeatable measurements well within Fluenta uncertainty specifications. This paper will report on the combined experiences of Saga Petroleum and Fluenta, both with respect to failure mode, repair, operational experience and the use of data.
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Document ID: 3B3EB472

Experience With Ultrasonic Flowmeters In Fiscal Applications For Oil Products(-)
Author(s): C.J. Hogendoorn, A. Boer
Abstract/Introduction:
Last years the number of applications for fiscal metering of oil (-products) with a multi beam ultrasonic flowmeters has been increased significantly. The growing interest for this type of fiscal metering is mainly due to specific advantages. Besides the high accuracy and complete independence of viscosity, the long-term stability is very good. These attractive properties are a result of an essentially different measuring principle. Multi beam ultrasonic flowmeters can be smoothly used in installations on the continent. In limited spaced offshore applications some specific features of an ultrasonic flowmeter must be taken into account, in the system design, to stay within the NPD repeatability requirements for turbine meters. This article explains how to realise a successful application of a multi beam ultrasonic flowmeter in situations with a small prover volume. This is explained starting from the fundamental measuring principle of an ultrasonic flowmeter. The paper is finished with a consideration of the future developments and some conclusions.
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Document ID: 77B8F0C1

Development And Installation Of The Able Ctm Ultrasonic Cargo Transfer Metering System On The Bp Amoco Schiehallion Fpso
Author(s): Peter Baldwin
Abstract/Introduction:
Late in 1993 whilst exploring the deep waters to the west of the Shetland Isles the semi-submersible drilling rig, the Ocean Alliance, discovered the Schiehallion oilfield. The Schiehallion field is located beneath 400M of some of the most hostile sea in the UK Continental Shelf. Field reserves were estimated at 425 million barrels and it was anticipated that as many as 29 subsea wells in 4 producing clusters could be required for recovery. It was decided that use of the emerging FPSO technology would be most suited to the task and the worlds then largest new build FPSO vessel Schiehallion was commissioned.
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Document ID: 95D190C8

Two Years Of Fiscal Performance By The Liquid 5 Path Krohne Altosonic-V Ultrasonic Meter At The Vigdis/Snorre Crossover Oil Measurement Station
Author(s): Maron J. Dahlstrm
Abstract/Introduction:
[Abstract Not Available]
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Document ID: 5575B7B5

Behaviour Of Venturi Meters In Two-Phase Flows
Author(s): J.P. Couput, V.de Laharpe, P. Gajan, A. Strzelecki
Abstract/Introduction:
Needs for accurate and reliable on line metering of two-phase flows (gas and/or liquids) are arising for fiscal and allocation reasons when subsea or topside installations are shared by several partners. This paper describes the work carried out by ELF EXPLORATION PRODUCTION and GAZ DE FRANCE in collaboration with the ONERA research centre to assess and develop accurate methods applicable for gas metering with condensate (wet gas). After a review of allocation metering requirements and available techniques for flow rate measurements in high gas fraction conditions (GVF95%), this paper deals with the behaviour of Venturi flow meters in similar two-phase flows. The applied methodology, which combines experimental laboratory testing in ONERA, numerical simulation and field evaluation is described. The preliminary results obtained on the Venturi meter in different two-phase flow configurations (annular, mist) are presented. The influence of some flow parameters (liquid content, flow pattern) on the Venturi behaviour is discussed.
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Document ID: 2C052EEF

Use Of Venturi Meters In Multiphase Flow Measurement
Author(s): A R W Hall, m J
Abstract/Introduction:
This paper describes a project to investigate the performance of Venturi meters in multiphase flows. A range of Venturi meters spanning three diameter ratios and three inlet convergent angles was evaluated across a comprehensive range of multiphase flow conditions in the multiphase flow measurement facility at NEL. The Venturi meters were evaluated in an uninterrupted 4-inch horizontal pipe run, without any mixing. The first stage of the project focused on development of appropriate instrumentation, using standard differential pressure transmitters and a clamp-on gamma densitometer, followed by the full evaluation of the meters. Based on the results of this programme, one Venturi meter was selected for final evaluation using further refined instrumentation to collect data at a higher frequency. Evaluation of this final meter together with more detailed analysis of the data completes this paper.
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Document ID: 27053529

Upstream Pipe Wall Roughness Influence On Ultrasonic Flow Measurement
Author(s): H.J. Dane, R.Wilsack
Abstract/Introduction:
In high-pressure natural gas pipelines, installation requirements of modern ultrasonic flow meters usually only specify an upstream pipe length, without mentioning wall roughness. Since no data were available to support a specification, Measurement Canada and TransCanada PipeLines decided to conduct a series of tests under well-defined conditions. This document reports the results. The tests were carried out at the Ruhrgas test facility Pigsar in Germany, where two 12 Q.Sonic 3-path ultrasonic flow meters (Instromet) were repeatedly calibrated at about 45 bar, while various pipes of different roughness were mounted upstream. Two Ruhrgas engineers measured the wall roughness of the pipes using ISO 9001 certified standard methods. Over the range of conditions investigated, an increase of the roughness Ra from about 5 m to probably 20 m appears to increase the meter reading by about 0.1 - 0.2 %.
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Document ID: 4205F22B

The Effects Of Reynolds NUMBER,WALL ROUGHNESS,AND Profile Asymmetry On Single- And Multi- Path Ultrasonic Meters
Author(s): Klaus J. Zanker
Abstract/Introduction:
A simple power law velocity profile is used to study the effects of pipe roughness and Reynolds Number (Re) on ultrasonic meter performance. Considered here are two measurement methods. The first utilize a single bounce path through the pipe center, and is common to multipath as well as single path meters. The second employs four parallel chordal paths, (e.g. Daniel SeniorSonic). The single path centerline measurement requires typical corrections from 4% to 8% for changes in velocity profile due to variations in pipe roughness and Re. A correction for Re can be calculated from additional information on fluid density and viscosity, but changes of roughness with time cannot be measured, and hence cannot be corrected. It will be shown that the four path meter does an excellent job of integrating the velocity profile to give the correct flow rate over a wide range of both Re and roughness. A mathematically generated profile similar to that from a single bend is used to study the effects of asymmetry on the performance of both measurements. The centerline measurement varies over about 1.5%, depending on the path orientation relative to the asymmetry. Unfortunately applying a typical Re correction then creates a bias error of about 4%. In contrast, the four path meter accurately integrates the velocity profile to give an answer within 0.2% of the flow irrespective of orientation. Furthermore the four-path meter is capable of recognizing the changes in operating conditions.
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Document ID: F2525800


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