Velocity Profile Measurement In An Orifice Meter Calibration System For Natural Gas
Author(s): J. J. S. Shen, V. C. Ting
Abstract/Introduction:
This paper presents some of the results of an orifice research project regarding the system effects on the accuracy of orifice metering. Experiments were conducted on Chevrons natural gas flow calibration facility in Crane, Texas. Three aspects of the flow system that may influence measurement results are studied: velocity profiles were measured using directional pitot probes at metering location, pressure transducers stability was examined over time and for varying temperature, and comparisons were made of orifice meters operating alone and in series with an upstream meter. In comparative calibration tests, a bank of critical flow nozzles was used to determine the reference flow rate. Experimental results have verified that the base case of a fully developed flow with no interference between meters was achieved in the calibration facility. This study ensures proper entrance conditions and accuracy of measurements in future work.
Go to Download Page
Email Reference
Document ID:
0B58847B
Orifice Measurement In Perturbated Conditions : Sources Of Error And Possible Corrections
Author(s): Pierre Gajan, Patrick Hebrard, Bernard Platet
Abstract/Introduction:
In order to improve the flowrate measurements obtained by means of orifice plates when they are used in pipes where the flow characteristics deviate from the fully developped conditions required by standards, two kind of approaches are possible. The first one is to recreate these required conditions by means of especially designed devices in the second one, the perturbation effects are taken into account in the flow rate computation. In this paper, result of the cooperation between a research center and two industrial partners,an example of each approach is presented. For spatial disturbances, a resulting flow quite independant of upstream conditions is given by a new type of flow conditioner, the geometry of which is determined by a simple computation. For pulsating flow, new unsteady analytical models(in which coefficients, generally empirical, are here determined from instantaneous measurements) are presented and tested to show their ability in improving the metering error corrections.
Go to Download Page
Email Reference
Document ID:
DEF99A58
Attenuation Effects Of Pipe Roughness On Swirl And The Implications For Flow Meter Installation
Author(s): R C Mottram And m S Rawat
Abstract/Introduction:
Experiments are described in which the decay of swirling flow induced by an offset bend combination was measured in both smooth and artificially roughened 80 mm bore pipes. Measurements were also made of the changes in the calibration of flowmeters placed downstream of the bend combination with varying settling lengths of both smooth and rough pipes. These flowmeters included square-edged orifice plates and a vortex meter with a rectangular section bluffbody. It was found that the pipe roughness had a very marked effect on the rate of swirl decay and the minimum settling length of straight pipe required for the orifices. It is suggested that the existing specifications found in flow measurement standards for minimum straight pipe lengths for installations of this kind should be reviewed to take into account pipe roughness effects.
Go to Download Page
Email Reference
Document ID:
3C172B18
Officially Approved Gas Metering In W-Germany - The Establishment Of The Vortex Meter
Author(s): H. J. Kastner
Abstract/Introduction:
Years of experience in various applications were necessary to establish the vortex gasmeter Type WBZ 08 in all fields of the officially approved gas measurement. Results with vortex gasmeters of sizes 3 to 16, calibrated under operating conditions, running in series with turbine gasmeters, controlled and monitored by flow computers along with pressure, temperature and density transducers have finally shown that they are able to improve long time stability and availability of the flow measurement systems in the high pressure gas field.
Go to Download Page
Email Reference
Document ID:
6AB8FBBA
Mathematical Model Of Shedding Vortices
Author(s): Boris A. Kamentser, Chris Watson
Abstract/Introduction:
An analytical technique using the Eulers equations is developed to derive formulae for the frequency and amplitude of pressure pulsations produced by shedding vortices behind a bluff body in a flowing stream of fluid. A two dimensional model is used. It is shown that only the first and second harmonics will be generated. The amplitude of the first harmonic is zero in the center plane of symmetry behind the bluff body, but the amplitude of the second harmonic is not zero in the center plane. Good agreement is found between experimental data and theory.
Go to Download Page
Email Reference
Document ID:
88057EFF
A Flow Conditioner-Nozzle Meter For High Accuracy
Author(s): Andrew A. Fejer, Thomas C. Corke
Abstract/Introduction:
A new concept flow meter based on properly designed converging nozzles is proposed over the more commonly used orifice plate flow meters. In conjunction with upstream flow manipulators to eliminate all flow non-uniformities, steady flow calculations can be made to a much greater accuracy. The possibility of accurately predicting by analytical means the the rate of flow through converging nozzle flow meters makes it possible to design meters that have an acceptable accuracy independent of their location in the pipeline and usable over a wider range of operating conditions.
Go to Download Page
Email Reference
Document ID:
D6BA4B78
First Steps Toward The Verification Of Orifice Metering Stations Of Flowrate In Hungary And Difficulties In Application Of ISO 5167 Standard
Author(s): Peter Boloni
Abstract/Introduction:
Changes in economical conditions have called for selling fluids on the basis of orifice metering system with known and lower uncertainties than previously. Analysis of the national gas metering and the settling of accounts has proved that reducing the measuring uncertainty sensibly reduces the expected loss of the gas supply company. It was obvious that the ISO 5167 standard did not contain sufficient information on the determination of the measuring uncertainty of the supplied gas quantities.
Go to Download Page
Email Reference
Document ID:
904949DF
Comparison Of Energy Measurement By Volumetric Vs. Mass Procedures
Author(s): Robinson Ord, Fred Debbrecht, Ron Blohm
Abstract/Introduction:
Energy flow computation methods are studied for orifice meters, using chromatographs to estimate heating values and either chromatographs or vibrating element instruments to estimate density and/or relative density. Two alternative methods for determining energy flow are compared - a volumetric method and a mass method. Conditions are: typical natural gas at 200 to 1000 psig (1481 TO 6996 kPa) and 0 to 180 F (-17.8 to 82.2 C). At relatively high levels of inerts (e.g. N2 and C0), the volumetric method yields better results. However, at typical inerts levels, the mass method is preferred. In either case, vibrating element densitometers are shown to have a useful role, especially at higher pressures and in larger pipes.
Go to Download Page
Email Reference
Document ID:
E5E625CE
Installation Effects: Results Of The Eec 100 mm Orifice Plate Project
Author(s): John m. Hobbs, Jane A. Sattary
Abstract/Introduction:
Over the past six years an extensive investigation has been undertaken under the joint sponsorship of the Commission of the EEC (the European Economic Community) and the participating organizations into the discharge coefficients of orifice plates and especially in the accurate measurement of natural gas. A broad description of the programme and some results of the work have already been published. The tests described in this paper were to provide data on the installation straight lengths required after disturbances caused by various fittings including multiple bends, both In the same plane and in perpendicular planes, with and without the use of flow straighteners. While, in general, the upstream lengths given for the multiple bends in ISO 5167 were found to be sufficient to keep the deviations of the coefficients within the tolerances given, shorter distances such as those given in AGA 3 had significant effects.
Go to Download Page
Email Reference
Document ID:
DAFAB921
A Study Of Edge Sharpness Effects Measured During The Eec Orifice Plate Coefficient Programme
Author(s): E. Antony Spencer
Abstract/Introduction:
The EEC Orifice Plate Coefficient Project is being carried out under the joint sponsorship of the Commission of the EEC (the European Economic Community), and a number of participating organizations who are interested especially in the use of orifice meters for the accurate measurement of natural gas. In the course of the Project the plates themselves have been the subject of numerous physical examinations - notably of the edge sharpness - to check their continuing acceptability to the ISO 5167 Standard. The paper gives the background of how edge sharpness has been specified in the standards and briefly describes the different techniques used for its measurement. Earlier studies are analysed and applied to the results obtained in the EEC tests. It is concluded that normal plates give coefficients around 0.2 percent above the predicted values and a more objective method of measuring the edge profile must be adopted universally.
Go to Download Page
Email Reference
Document ID:
295B5AC7
Thermophysical Property Data Evaluation On Organic Compounds - The Present Status In The U.S.A.
Author(s): Kenneth N. Marsh
Abstract/Introduction:
The present state of data banks and data evaluation efforts in the U.S.A. with regard to physical and thermodynamic properties on organic compounds is reviewed. The procedures for data compilation, selection, and evaluation at the Thermodynamics Research Center (TRC) is outlined and the relations between the evaluation work at TRC and other data evaluation efforts is discussed. A detailed account of the TRC data bases for both original measurement and evaluated data is given. The state of compilations and evaluation of the thermodynamic properties of mixtures of organic compounds is briefly discussed.
Go to Download Page
Email Reference
Document ID:
1476E413
New Data For The Quadraht-Edge Orifice
Author(s): Charles L. Britton
Abstract/Introduction:
New experimental data is presented for both quadrant-edge and sharp-edge orifice plates used in low Reynolds number applications. Twelve different orifice plates with diameter ratios (Beta ratios) from 0.25 to 0.54 were calibrated in 76mm (3) and 102mm (4) pipe using flange taps. A white mineral oil with a kinematic viscosity of approximately five centistokes was used as the calibration fluid which resulted in a pipe Reynolds number range of from 290 to 45,000. Calibration data is presented for piping lengths that meet the requirements of AGA (ANSI/API-2530) .
Go to Download Page
Email Reference
Document ID:
19C2F0E4
Measurement Of Natural Gas At Low Temperatures Using Displacement Type & Turbine Meters
Author(s): Michael A. Howard
Abstract/Introduction:
Meters are typically proof-tested by their manufacturers in climate controlled conditions where both the ambient and gas temperature approximate 21C (70F). In some parts of North America, ambient temperatures can be as low as -40C (-40F) and gas temperatures, if not heated, can be as low as -29 C (-20F). How does this affect gas measurement accuracy and how can meters be proved at these operating conditions? In the past. Northern Natural Gas Company had always heated our natural gas prior to measurement in an effort to maintain the gas temperature in a range of 0 to 5C. heaters useo tor this purpose consumed from .1 to .25% of the total gas sold through these meters. In an effort to reduce operating expenses, we began evaluating the impact of eliminating heater operation. This led to extensive field testing by our measurement technicians which produced an alarming indication that the meters were slowing down from 2-5% when operated at low gas temperatures.
Go to Download Page
Email Reference
Document ID:
EF1CC870
The Impact Of Microprocessor-Based Transmitters On Orifice Flowmeter Rangeability
Author(s): Stanley L. Whitman
Abstract/Introduction:
The use of microprocessors in differential pressure transmitters has allowed a significant increase in the potential on-line turndown of orifice flowmeters. Limitations of standard electronic circuitry that have prevented wider rangeability of these flowmeters have been overcome, extending their turndown from a nominal 3:1 to potentially 7:1. The impact of this technology can be worth as much as 21,000 for many applications.
Go to Download Page
Email Reference
Document ID:
7EA93F5F
The Advantages Of Microcomputer Volume Correction At The Meter Site
Author(s): Richard H. Schieber
Abstract/Introduction:
The gas industry is now seeing a wave of new electronic correctors and flow computers devices that are designed to be interchangeable with the large population of mechanical correctors that have been in service since the 1930s. These electronic instruments do the traditional Boyles and Charles Law corrections but with greater accuracy. Improved accuracy, however, is only part of potential benefits. Others are calibration ecise, major reductions in maintenance, complete application flexibility and data communication. There are also other considerations that should not be overlooked in electronic correctors. Factors such as reliability and upgradeability. This paper will discuss each of these design parameters, while making comparisons to mechanical correctors.
Go to Download Page
Email Reference
Document ID:
1E73C8C7
Flow Measurement Calibration Using Laminar Elements
Author(s): Richard K. Peelle
Abstract/Introduction:
This paper describes the design and calibration of the Laminar Flow Element System used to calibrate mass flow controllers at the Optical Waveguides Plant. The system is composed of five laminar flow elements piped and valved to allow nitrogen to be directed to a selected element. Common metering provides gas temperature, pressure, and LFE pressure drop. Calibration was performed at the National Bureau of Standards in Washington and NBS data regressed to David Todds mathematical model for the calculation of LFE coefficients.
Go to Download Page
Email Reference
Document ID:
EC36AA6E
Facility For The Mass Flow Rate Calibration Of High Accuracy Fuel Flowmeters
Author(s): D. William Craft
Abstract/Introduction:
A facility for the precise calibration of mass fuel flowmeters is being installed at the Aircraft Instruments Department of the General Electric Company at Wilmington, Massachusetts. This facility is referred to as the Test and Calibration Systems (TACS). It is believed that it will be the most accurate test facility available for the calibration of jet engine fuel flowmeters over a wide range of operating conditions. The TACS uses a precision device for volumetric flow rate measurement in conjunction with a precision fluid density measurement. The product of (1) the volumetric flow rate measurement and (2) the density measurement results in true mass flow rate determination.
Go to Download Page
Email Reference
Document ID:
CDD617BB
Densitometers For Sales Gas Metering
Author(s): Ottokar Brandt
Abstract/Introduction:
The paper discusses the problems involved in the measurement of large quantities of gas of varying composition at high pressure for energy billing. Vibrating-element densitometers are almost ideally suited for this application. At numerous international sales gas metering stations in Western Europe and, more particularly, in the Federal Republic of Germany, these instruments have been employed for many years. The method of measuring density by density cells as well as improved designs and installation techniques are discussed. The paper analyzes the effect of the velocity of sound on density measurement and reports on tests made by the weighing method to study what corrections can be made for the velocity of sound effect. These tests also provided information on the validity of the densities published by the U.S. National Bureau of Standards for methane and nitrogen. The paper concludes by a review of field and laboratory calibration uncertainties.
Go to Download Page
Email Reference
Document ID:
CD91E770
Turbine Flowmeter And Real Time Computation As A Diagnosis Tool For Unsteady Flows
Author(s): Francois Liousse
Abstract/Introduction:
It is well known that almost every type of currently used flowmeters exhibit some deviations in evaluating a mean flow value from steady state calibration when submitted to unsteady flow conditions such as pulsations or intermittency. Some methods of correction are availaible, depending on the metering device type and on the knowledge of the time dependent characteristics of the flow, mainly pressure and velocity fluctuations (1). The way proposed in this paper to determine the flow characteristics is the use of a turbine flowmeter associated with a computer including a model of the dynamic behaviour of the flowmeter rotor. A three steps process is described : i) establishment of the dynamic behaviour equation. ii) parameters identification - Results. iii) use of the model for real time signal corrections and evaluation of flow characteristics.
Go to Download Page
Email Reference
Document ID:
CE918CB1
Comparison Of Flowmeter Calibration Equipment Using Vortex And Turbine Meters
Author(s): Sandor Kun
Abstract/Introduction:
Three different flowmeter testing facilities were compared by means of a tandem turbine and vortex meter package. Using the combination of the two type of flowmeter did not solve the difficulties on the field of the long time stability of the flowmeter transfer standard. But really marks out the way of the solution. In our lecture (8) published in 1983 working out the investigation results of series connection of turbine meters (short time stability, long time stability) we arrived at the assumption, that by combining the verified good short time stability of turbine meters with the probably good long time stability of Vortex meters we succeeded in creation of a more reliable and more accurate measuring connection than the transfer standard known and used until now for the dynamical comparison of standard equipment.
Go to Download Page
Email Reference
Document ID:
08707A45
Performance Of A Self-Adjusting Gas Turbine Meter
Author(s): Winston F. Z. Lee
Abstract/Introduction:
Self-adjusting turbine meters have been used for high accuracy custody transfer gas flow measurement since 1980. Each of these meters has a free running sensor rotor (placed downstream of the main or conventional rotor) which senses and responds to changes in the exit angle of the fluid leaving the main rotor. The difference and the ratio between the main rotor output and sensor rotor output provide the meter with the unique and outstanding capabilities of self-correcting and self-checking for upstream swirl and change in retarding torques. Moreover, through its microprocessor based electronic readout, the application of the unique logic using the criterion of its normal range of output ratio between main rotor and sensor rotor greatly improves the meters performance under many non-steady flow conditions.
Go to Download Page
Email Reference
Document ID:
47BD041A
Comprehensive Study Of Methane + Ethane System
Author(s): W. m. Haynes, R. D. Mccarty
Abstract/Introduction:
This paper reports on the use of the methane-ethane system as a model for developing and testing predictive techniques for mixtures. Comprehensive data have been obtained for both thermodynamic (PVT, heat capacity, sound velocity) and transport (viscosity, thermal conductivity) properties of three mixtures of methane and ethane, as well as for both components. The sound velocity and heat capacity data serve as extremely stringent tests for evaluating the performace of calculational techniques, as well as providing key information essential for optimizing the models. A critical enhancement in the thermal conductivity was observed for this system current theory does not predict such behavior for mixtures.
Go to Download Page
Email Reference
Document ID:
CF3E341D
Performance Of A Self-Adjusting Gas Turbine Meter
Author(s): Winston F. Z. Lee
Abstract/Introduction:
Self-adjusting turbine meters have been used for high accuracy custody transfer gas flow measurement since 1980. Each of these meters has a free running sensor rotor (placed downstream of the main or conventional rotor) which senses and responds to changes in the exit angle of the fluid leaving the main rotor. The difference and the ratio between the main rotor output and sensor rotor output provide the meter with the unique and outstanding capabilities of self-correcting and self-checking for upstream swirl and change in retarding torques. Moreover, through its microprocessor based electronic readout, the application of the unique logic using the criterion of its normal range of output ratio between main rotor and sensor rotor greatly improves the meters performance under many non-steady flow conditions. Recently, self-adjusting turbine meters have been performance tested under various conditions of operation by Gaz de France, British Gas, and Northern Natural Gas of U.S.A. This paper presents some of this test data to demonstrate the unique and outstanding performance of a self-adjusting turbine meter.
Go to Download Page
Email Reference
Document ID:
3901B802
The Effect Of Upstream Installation Conditions On The Performance Of Small Liquid Turbine Meters
Author(s): Brian C. Millington, Colin W. Adams, Nicholas W. King
Abstract/Introduction:
This paper quantifies shifts in meter characteristics brought about by positioning either a 90 elbow or two mutually perpendicular 90 elbows or a gate valve just upstream of nine commercially available turbine meters. Meters varied considerably in size and geometry, the range covered being 12-37 mm, and rotor blades being either twisted, flat or T shaped. It has been shown that the double bend configuration produces the largest meter factor error for all meter sizes and types, however, the nature of the error both in magnitude and direction followed no discernable pattern - some meters exhibiting a reduction in meter factor when the upstream flow was swirling in the direction of the rotor. It was noted though that meters with tube bundle integral flow straighteners always had errors in the expected direction and the magnitude was relatively small, being at most 1 per cent.
Go to Download Page
Email Reference
Document ID:
50A8ECFA
Api-Dippr Evaluation Of Petroleum Data For The Industry
Author(s): Thomas E. Daubert
Abstract/Introduction:
Over twenty-five years ago, Penn State became first involved in property data projects when the major petroleum companies in the United States through the American Petroleum Institute began a project in the Department of Chemical Engineering with the purpose of developing a technical data book. From this effort came the Technical Data Book - Petroleum Refining, which has become widely adopted by the petroleum industry worldwide. This loose-leaf book has had several editions with revised and additional chapters published almost every year by API. Beginning in 1980, two new projects - the Data Compilation Project and the Data Prediction Manual Project (analogous to the Technical Data Book project) were begun at Penn State under the auspices of the Design Institute for Physical Property Data of the American Institute of Chemical Engineers. Publication of both projects in loose-leaf form by AIChE is underway with completion of release of the remaining chapters of the Data Prediction Manual first edition scheduled for 1987 and continuous publication of additional Data Compilation tables over the next several years. Also in the early 1980s the Gas Processors
Go to Download Page
Email Reference
Document ID:
04E2B513
Gas Flow Measurement Improvement By Accurate Thermodynamic Properties Correlation
Author(s): K. E. Starling, J. L. Savidge, S. Shankar, T. Reid
Abstract/Introduction:
Recent correlation work sponsored by the Gas Research Institute is shown to provide improved accuracies for thermodynamic properties used in gas flow measurement. The basis for these correlations and their improvement over earlier methods are discussed. Development of a new highly accurate equation of state for prediction of the supercompressibi1ity factor and other properties of natural gases has been sponsored by the Gas Research Institute to meet gas industry needs for accurate natural gas flowrate measurement procedures. Work from 1981 through 1984 targeted pipeline quality natural gases and gases with large amounts of carbon dioxide and nitrogen (1). Presently, this work is being extended to include accurate prediction of the supercompressibility factor of wet and/or sour natural gases and to provide accurate prediction capabilities for important quantities such as the sonic velocity and critical flow factors needed for sonic nozzle calculations.
Go to Download Page
Email Reference
Document ID:
367660E5
Microwave Apparatus For Measurement Of Phase Boundaries
Author(s): W. J. Rogers, F. Fontalba, J. C. Holste, K. R. Hall, P. T. Eubank
Abstract/Introduction:
This manuscript describes a novel apparatus for the direct measurement of phase boundaries in corrosive fluid mixtures to 1700 bar and 588 K. The apparatus measures changes in a static microwave energy field caused by changes in sample properties. On a phase boundary, shifts in the microwave frequency and power accompany the formation of the second phase. This new method does not involve optical observation of the sample, interpolation of isochores, or composition analyses of samples drawn from the sample cell. Only small sample cell volumes (10 cm ) are required. This microwave technique is effective with all types of fluids, light and heavy, nonpolar and polar, inert and corrosive, and it performs well at extreme conditions of pressure and temperature.
Go to Download Page
Email Reference
Document ID:
01DA6FE1
Speed Of Sound In Natural Gas Mixtures
Author(s): Robert D. Mccarty
Abstract/Introduction:
Accurate values for the speed of sound in natural gas mixtures are important in the application of sonic metering devices and in many design applications. In the case of mixtures, it is not possible to obtain experimentally determined speed of sound data for all possible compositions of the pure components found in natural gases. The alternative is a mathematical model of acceptable accuracy which allows the prediction of the speed of sound at an arbitrary state point and composition. This paper describes the state of the art for the prediction of the speed of sound for natural gases.
Go to Download Page
Email Reference
Document ID:
2AE09C71
High Precision Real-Time Gas Flow Measurement
Author(s): David F. Kee
Abstract/Introduction:
Gas measurement can now be done in the field continuously, with near laboratory precision. The accuracy of any metering system can be affected by installation effects (jetting, swirl, etc.), by subtle changes in the metering device with time (wear, dirt build-up, etc.), and by changes in gas composition which affect the magnitude of supercompressibility. By incorporating sonic nozzles and other instrumentation for calibrating meters in-situ (in position) and for measuring the supercompressibility directly on-line, an integrated gas measurement system continuously defines a standard cubic metre (foot), traceable to laboratory standards, using digital computers. This paper explains how the sonic velocity correction factor is sensed during volume meter calibration using sonic nozzles and how the real-time supercompressibility is measured, instead of simply resorting to gas analysis and mathematical models that approximate real gas behavior. A description of how to calibrate each element, using laboratory devices to provide certification, is detailed.
Go to Download Page
Email Reference
Document ID:
044BDE03
Real Time Measurement System Design And Operational Considerations
Author(s): Brian J. Mcconaghy
Abstract/Introduction:
The use of micro-processors in conjunction with electronic inputs for the purpose of performing on-site volume and energy calculations, is gaining popularity in Canada and the United States. The incorporation of computer based, on-site metering for purposes of natural gas custody transfer measurement has been a relatively slow process in North America due to the established chart based systems and the age and size of the gas transmission and utility systems. Acceptance of this technology has been further hampered by the broad familiarity and acceptability of conventional chart metering and the lack of trend and audit data available from standard flow computer systems. In confronting this situation NOVA, AN ALBERTA CORPORATION combined innovative engineering, practical experience, and available technology to develop a real time measurement system which provides significant benefits over chart recorder devices and off-the-shelf flow computers. A sequel to the measurement system is the extensive operating experience gained in the installation, calibration and maintenance of electronic natural gas measurement equipment. This experience has identified specific areas of operating concern and resulted in testing of several electronic static and differential pressure transmitters. Tests have included effects of high pressure calibration, temperature, and process fluid effects on transmitter accuracy. This operating experience and testing has provided the knowledge necessary to establish effective selection, installation, calibration, and maintenance procedures.
Go to Download Page
Email Reference
Document ID:
B62BA046
Improved Effectivity In Measurement And Control
Author(s): Wayne 0. Wilson
Abstract/Introduction:
Electronic equipment is becoming more predominant in the natural gas industry every day. Computerized flow measurement is becoming an accepted replacement for mechanical charts and integrators. Process chromatographs incorporate electronic modules that measure composition and calculate BTU, specific gravity, compressibility and other variables. Continued improvements and cost reductions in microcomputers, microwave communications, modems and electronic equipment in general have opened the doors to vast improvements in data handling. This paper should stimulate the user to consider the overall objective when planning a gas measurement system. These include the data movement method, long term data retention and even the customer billing procedures. An effective overall system requires all of the components to operate together. This can only be accomplished by proper planning in the early phase of the program.
Go to Download Page
Email Reference
Document ID:
1CA97DB7
Fluid Flow Measurements Using Laser Diodes And Solid-State Detectors
Author(s): D. Dopheide, G. Taux, G. Reim, m. Faber
Abstract/Introduction:
The paper describes the possibilities of using laser diodes (LD) and highly sensitive photodiodes (avalanche diodes APD) in laser Doppler anemometry (LDA). The authors carried out comparison investigations between conventional LDA systems using gas lasers and photomultipliers and recently developed semiconductor elements. Furthermore, they experimentally investigated the accuracy which can be attained in local velocity measurement with respect to the uncertainties of frequency measurement and interference fringe spacing. The use of laser diodes offers new possibilities of flow measurement and opens up new fields of application. Various new optical configurations for flow and flowrate measurement are presented and described.
Go to Download Page
Email Reference
Document ID:
E4BBA001
Long-Term Variations In The Base Volume Of Pipe Provers
Author(s): A. T. J. Hayward, P. A. m. Jelffs
Abstract/Introduction:
Numerous pipe provers have been recalibrated by colleagues of the authors over the past twenty years, using the master meter/master prover method. Data are presented from groups of provers in three different countries, using different calibration equipment. The principal conclusions drawn are: (1) Control charts, showing how the base volume of a prover varies over a period of years, are valuable and should always be kept. (2) The claimed absolute accuracy of 0.05 per cent of the base volume is justified. (3) A major source of inaccuracy is the errors arising from variations in the calibrated volume of primary standard measures, which propagates downwards through the traceability chain. (4) Despite a widely-held belief to the contrary, the round-trip base volume of a bidirectional prover is almost as liable to change when detectors are replaced as the base volume of a unidirectional prover. (5) The initial calibration of a prover at the manufacturers plant is liable to change during transport and installation, and should therefore be repeated on site as early as possible.
Go to Download Page
Email Reference
Document ID:
F10806B6
The Development Of A Primary Standard For Calibrating Flow Meters On Gaseous Media
Author(s): Paul D. Olivier
Abstract/Introduction:
The need for calibrating flow meters of various types for gas service at elevated pressures is well documented. Currently various forms of Bell Provers or volumetric type glass tubes are used as primary standards at or near atmospheric pressure with reasonable precision, and nozzles or venturies are used at elevated densities. In many cases the flowmeter being calibrated has the potential of being more precise than the standard its being calibrated against. Flow Technology, Inc. has developed a primary positive displacement volume-time standard capable of calibrating flow meters at any desired density up to pressures of almost 1500psia. Almost any media can be used in the system.
Go to Download Page
Email Reference
Document ID:
C814010F
A Large Capacity, High Accuracy Oil Flow Test Facility
Author(s): Charles L. Britton
Abstract/Introduction:
This paper describes a new oil flow test facility that has been recently constructed and put into operation at CEESI (Colorado Engineering Experiment Station, Inc.)* The facility presently uses a mineral oil with a kinematic viscosity of approximately 5 centistokes as the calibration fluid and can measure volumetric flowrates from 0.1 to 284 cubic-meters/hour (0,5 to 1250 GPM). It is possible to change the tluid if a different viscosity is required. The oil flow test facility was designed and constructed by CEESI under a contract with the American Petroleum Institute (API) Orifice Project Management Committee. This facility was used in the development of a data base for flange-tap orifice meters at low KeynoIds numbers.
Go to Download Page
Email Reference
Document ID:
53BE4D5A
An Intercomparison Of The High-Pressure Gas Flow Calibration Facilities At NEL East Kilbride, Uk And Kf Vniiftri, Kazan, Ussr
Author(s): William C. Pursley, John Reid
Abstract/Introduction:
The paper describes the first part of an intercomparison programme between the primary gas flow measurement facilities in the UK at NEL, East Kilbride and in the USSR at KF VNIIFTRI, Kazan. The transfer standards used for the intercomparison and the comparison criteria are described together with an account of the facilities and procedures used. The results of the initial tests show that the agreement between the, two facilities is within the uncertainty claimed for each facility, although anomalies exist which remain to be examined in the later stages of the programme.
Go to Download Page
Email Reference
Document ID:
A161EB21
A Six-Laboratory Intercomparison Of Water Flow Measurement Facilities
Author(s): Frank C. Kinghorn, David J. m. Smith, Andrew Mckay
Abstract/Introduction:
A transfer standard flowmeter package, consisting of 200 mm diameter pipework with two orifice plates separated by a length of pipework containing a flow straightener, was designed and constructed at NEL to enable an intercomparison of the worlds major water flow measurement facilities. It has been tested in the Netherlands, Federal Republic of Germany, England, USA, and Japan between 1980 and 1986, being returned to NEL on several occasions during the period for check tests. The calibration of two flowmeters in series permitted the use of a statistical analysis technique first proposed by Youden (1) to identify whether discrepancies between the results from different laboratories were significant and whether they arose from the reference flowrate measurement methods used, the differential pressure measurements, or the velocity distribution approaching the test section. Although discrepancies were detected, the results from all laboratories lay within about 0.25 per cent of the overall mean, indicating very good agreement.
Go to Download Page
Email Reference
Document ID:
3E9DBB22
On-Site Calibration Of Liquid Flow Meters Using The Radiotracer Transit Time Method
Author(s): Risto Kuoppamaki, Heikki Turtiainen
Abstract/Introduction:
Flow meters belong to the category of instruments which are especially sensitive to the measurement environment. Hence the most reliable way to assure reasonable accuracy is to calibrate the flow meter on site, under the actual measurement conditions. The radiotracer transit time method has now been developed into a highly practical on-site calibration method by the introduction of the 137-Cs/137m-Ba radioisotope generator to supply the very short-lived (2.6 min) 137m-Ba radiotracer and a microprocessor unit carrying out the measurement digitally and computing the flow rate immediately. The whole set of equipment is easily portable. To reach a high accuracy level in industrial pipelines with complicated structures, practical instructions for detector location were developed to eliminate profile effects caused by bends, valves, etc. By using these and totally digital transit time computing, an overall accuracy level of +/- 1...2 per cent is achieved even in pipelines containing a straight section of no more than 20 pipe diameters.
Go to Download Page
Email Reference
Document ID:
ADDE49B0
Comparison Of Computation And Ldv Measurement Of Flow Through Orifice And Perforated Plates, And Computation Of The Effect Of Rough Pipework On Orifice Plates
Author(s): Michael J. Reader-Harris, William Keegans
Abstract/Introduction:
This paper presents work on the effect on orifice plates of two upstream flow conditions. The first half of the paper examines the effect of rough pipework on the discharge coefficients of orifice plates over a range of Reynolds numbers and shows that the change in discharge coefficient is approximately proportional to the change in friction factor. The advantage in having a few diameters of smooth pipe immediately upstream of the orifice is shown. The second half of the paper presents measurements made using laser Doppler veloclmetry (LDV) In a rig comprising two bends in perpendicular planes, a perforated plate flow straightener and an orifice plate, together with computational comparison.
Go to Download Page
Email Reference
Document ID:
12711E1F
The Basic Coefficient Data Determined In The Eec 2 50 mm Orifice Plate Program
Author(s): B. Harbrink, H. Bellinga, J. De Jong, F.C. Kinghorn, R. Norman, J.P. Vallet
Abstract/Introduction:
In 1978, the Directorate General XII of the Commission of the European Communities approved a major study to provide improved information on the discharge coefficients of orifice plates. The objective of the project was to create a wide data base going beyond Professor Beitlers data from the early thirties for flange and D and D/2 tappings and the data of the West German VDI Committee for corner tappings. These two sets of data represent the basis of the Stolz equation in the current ISO Standard 5167. A similar project was launched by API and AGA/GRI in the U.S.A. in the mid-seventies. In the EEC Ccimpaign, orifice plates of six different diameter ratios varying between 0.2 and 0.75 and two different thickness sizes for DN 100 and DN 250 pipework were tested. The pipe Reynolds numbers ranged from 5 x 10 to 3.5 x 10*. The basic calibration data for the DN 100 orifice plates have already been published by the EEC (1). A paper on the results of a first approach to the analysis of these data was presented at the NEL Conference in June 1986 (2).
Go to Download Page
Email Reference
Document ID:
F9CFC768
Determination Of The Basic Orifice Factors For Two Commercial 40.64 cm (16) Meter Runs At High Reynolds Numbers
Author(s): Emrys H. Jones, Jr., Ken R. Ferguson
Abstract/Introduction:
A detailed description of a Chevron flow calibration facility in Venice, LA, is presented along with results of the calibration of two 40.64 cm (16) orifice meter runs. The facility is capable of proving up to 131 m3/s (400 MMSCFD) of processed natural gas flow at approximately 6.9 MPa (1000 psig). The experimental data presented covers a beta ratio range from .27 to .71 and a Reynolds number range from 4 x 106 to 35 x 106. Discharge coefficients were determined by comparing the orifice flow to the flow from critical flow nozzles.
Go to Download Page
Email Reference
Document ID:
19F07762
The API/GPA Orifice Discharge Coefficient Project Data Base
Author(s): W. A. Fling, Jr.
Abstract/Introduction:
The American Petroleum Institute (API) and the Gas Processors Association (GPA) have completed a four year, research program to develop a new archival discharge coefficient data base for concentric, square edged, flange tapped orifice meters. The program measured discharge coefficients over a pipe Reynolds number range of 150 to 20,000,000, and resulted in approximately 21,000 new discharge coefficients. The conceptual design is presented that was followed for the three single phase, newtonian fluids viscous oil, water, and pipeline quality natural gas. The goal of the conceptual design was to clearly define the experimental map and the experimental pattern that would achieve an uncertainty in the discharge coefficient of 0.2 percent over a sufficiently large pipe Reynolds number range.
Go to Download Page
Email Reference
Document ID:
EE094B3A
Flowmeters Used In Internal Combustion Engines
Author(s): Vulko m. Kichev
Abstract/Introduction:
Due to the small flows running through the feed system of the internal combustion engines, the need for high precision of measuring the operation requires the use of only a few methods for flow-rate measuring known today. The supersonic phase measurement, the elastic suspention local resistance, the tachometer method, the chamber flowmeters and the hot-wire anemometers are of great significance. This paper studies and makes an evaluation of the accuracy of suitable methods and gauges for measuring the fuel consumption of internal combustion engines. The gauges considered here are mainly intended for use in vehicles, where the compactness and reliability of the measuring gauge are of primary importance. In flows running through the fuel-charging pipe from 0,5 to 5 A 20 cm /s, when using supersonic phase measuring, in order toobtain the required difference of lc, the generator freguency has to be over 2 MHz, which will make the comparing device work under hard operating conditions, thus making the equipment more expensive. The elastic suspension local resistance gauges possess distinct dynamic characteristics and meet the requirements for compactness and reliability of the measuring system. The accuracy of this type of gauges is in the range between 0,2 and 0,5% The turbine flowmeters are inaccurate for small flows at idle run of the internal combustion engines. The error in the range lowest limit exceeds 10%. The chamber flowmeters provide the required accuracy of measurement and are suitable for the purpose. Hot-wire anemometers may also ensure high precision if some corrections are made, but their software is too sophisticated and expensive.
Go to Download Page
Email Reference
Document ID:
5D73AD90
Master Meter Proving Orifice Meters In Dense Phase Ethylene
Author(s): James E. Gallagher
Abstract/Introduction:
Shell Pipe Line Corporation, cognizant of the importance of highly accurate orifice measurement for polymer-grade ethylene, embarked on a development program to improve the overall uncertainty of orifice metering. The programs goal was to successfully apply master meter proving techniques to dense phase ethylene orifice meter facilities operated on a mass basis. This paper presents the techniques and results of mass proving concentric, square edged, flange tapped orifice meters. All data were obtained on commercially operated metering facilities which are in compliance with ANSI 2530 requirements. Results indicate an overall orifice meter uncertainty tolerance of approximately + 0.31 percent is attainable when orifice meters are mass proved in situ using master meter proving techniques.
Go to Download Page
Email Reference
Document ID:
A9D2BB74
Field Evaluation Of Flowmeters
Author(s): Ian m. Hamilton
Abstract/Introduction:
The question of whether currently available flowmetering instruments are suitable for water industry use was one of several subjects for enquiry which emerged from a recent review of Instrumentation, Control and Automation (ICA) applications. To answer this question, an Evaluation and Demonstration Facility (EDF) has been established at the Witney sewage treatment plant. Instruments are being evaluated under field conditions so that users can determine which instruments are most suitable for any application. Two categories of instruments have completed their field evaluation (of twelve months duration): sewage flow in closed pipes, and sludge flow in closed pipes.
Go to Download Page
Email Reference
Document ID:
8885C63C
Numerical Investigations Of Two-Phase Flow Through Differential Pressure Type Flowmeters
Author(s): B.Dobrowolski, Z. Kabza
Abstract/Introduction:
On the basis of a two-dimensional mathematical model,dispersed two-phase flow through a pipe orifice and a Venturi meter has been analysed. The two-phase flow was treated as the motion of interpenetrating and interacting continuous fluids. As a result of numerical calculations it is found that the metrological performance of differential pressure flowmeters depends on the degree of non-equilibrity of the flow phenomenon, dependent on the value of the Stokes number. A simple correction function, including the influence of application conditions on the differential pressure in two-phase flow, has been worked out. The two-sided criteria,enabling the estimation of the range of applicability of the calculation method for single-phase fluids in case of the measurement of two-phase mixture,have also been proposed.
Go to Download Page
Email Reference
Document ID:
3CB368BB
Optical Volumetric Flowmeter
Author(s): Dariush Modarress, Medhat Azzazy
Abstract/Introduction:
A computer controlled nonintrusive volumetric flowmeter based on the application of laser anemometer for direct measurement of gas velocity in high pressure pipes is described. The flowmeter is based on the measurement of gas velocity at a number of points along one diameter. Two small laser sheets, one millimeter apart are projected into the flow. The instantaneous gas velocity is calculated by measuring the time of flight of micron-sized particles (present in the gas line) between the two sheets. Traversing of the two laser sheets, i.e., the measurement point, is remotely achieved through a translation of the optical head, all within a protective housing. The flowmeter is attached to a high pressure pipe spool and the optical access is achieved through a high pressure window. The design and fabrication of a laboratory prototype has been completed. In this paper, the design features of the flowmeter and topics such as accuracy and precision in relation with the optical flowmeter are discussed. Sample velocity profiles obtained for a fully developed pipe flow are presented and the total volumetric flow rates are calulated. Finally, the results of our measurement of the size and concentration of the particles in the gas pipeline are presented.
Go to Download Page
Email Reference
Document ID:
7FCF4555
Ultrasonic Gas Flowmeter, Gf Series
Author(s): Yoshiki Ito, Yasuhiro Kobori
Abstract/Introduction:
An ultrasonic gas flowmeter has been developed which provides the average velocity or the volume flow rate of gas flowing in a pipeline. The average velocity calculated from the difference of reciprocal transit times between a pair of acoustic probes allows no dependence on sound velocity in a gas as well as gas composition, pressure and temperature. The volume flow rates measured by an ultrasonic flowmeter have shown good agreement with those by a differential type one in the rates above 10 percent of flow range and better results in lower flow rates. The outlines and performance are presented in this paper.
Go to Download Page
Email Reference
Document ID:
963B3240
Ultrasonic Gas Flow Measurements In Reflection Mode In Underground Pipelines
Author(s): G.J. Broekgaarden, H. Lammerse
Abstract/Introduction:
A testprogram is carried out at the Gasunie laboratory to establish the capabilities of ultrasonic flowmeters to measure high pressure gas flow in underground pipelines. In this paper the background of the program is given and some problems related to ultrasonic flowmeters are discussed. Special attention is paid to the possibility of using different paths to determine the sonic pathlength and the degree of swirl. The latter capability gives the possibility to correct the measured flows for the effects of swirl. The results of the laboratory tests using a single path and tests using paths with one, two or even four reflections are given. In all these cases tests have been carried out in undisturbed as well as in disturbed flow. It appears that, although there are a lot of guestions still to be answered. ultrasonic flowmeters can be used in reflection mode in high pressure pipelines.
Go to Download Page
Email Reference
Document ID:
E8223F19
The Measurement Op High Pressure Natural Gas Plows Using The Pourpath Ultrasonic Flowmeter Developed By British Gas
Author(s): M.E. Nolan, J.G. Ohair, R. Teyssandier
Abstract/Introduction:
This paper summarises the development of a multi-path ultrasonic flowmeter. It describes the reasons for developing the meter and the principles on which it works. A detailed theory of the techniques is presented for the case with transducers set back from the flow and there is a simple analysis of the effect of swirl in meters with criss-cross chords. Test results obtained using prototype meters of 150 and 600 mm diameter are presented and confirm the accuracy of the technique in developed and disturbed flows. The experience of using a total of 6 different meters ranging in size from 100 to 1050 mm on operational sites, is described and shows that the meters are very reliable.
Go to Download Page
Email Reference
Document ID:
C57A93D6
Uncertainty Assessment In Flowmeter Calibration
Author(s): Frank C. Kinghorn
Abstract/Introduction:
Some of the principles and terminology to be used in applying statistical analysis to flowmeter calibrations and in presenting the results are described. There is particular discussion of the procedures for plotting calibration graphs, with examples showing how the wrong choice of coordinates can lead to misleading conclus ions. The practical problem of arriving at a best estimate of the discharge coefficients of orifice plates is dealt with, paying particular attention to current research programmes in the USA and Europe where calibrations of the same meters have been repeated in several laboratories. The difficult question of how to compute the uncertainty in the resulting data is addressed and one solution proposed which appears to overcome many difficulties.
Go to Download Page
Email Reference
Document ID:
7CF6CB58
Unaccounted-For Gas In Natural Gas Transmission Systems
Author(s): Roger Norman, Peter Jepson
Abstract/Introduction:
In the first part of the paper an error analysis is used to ascertain the uncertainty on the unaccounted-for gas figure for high pressure natural gas transmission systems. The second part of the paper outlines a simple method of recognising the magnitude and time of significant changes in unaccounted-for gas. In the last part of the paper a number of case studies are presented which show the effect of some typical phenomena on the metering accuracy and hence unaccounted for gas in transmission systems.
Go to Download Page
Email Reference
Document ID:
E3C0CCCE
Certifying Flcw Conditions At Gas Pipeline Metering Installations
Author(s): Cecil R. Sparks, Robert J. Mckee
Abstract/Introduction:
It is generally recognized that pulsations and other adverse flow conditions at natural gas metering installations are major sources of metering errors. Recent research sponsored by the Southern Gas Associations Pipeline and Compressor Research Council (SGA-PCRC) has made significant strides in defining the effects of unsteady flow on metering accuracy, and in providing diagnostic techniques for assessing the severity of conditions in the field. This paper reports on the major sources of pulsation-induced errors in orifice meters: both in the primary element and in the secondary sensing and recording systems. Field data is shown to corroborate the pulsation effects described, and to demonstrate the usefulness of field certification techniques in identifying and quantifying these errors.
Go to Download Page
Email Reference
Document ID:
BF1F89CF
An Investigation Of The Effectiveness Of Flow Conditioners
Author(s): James S. Humphreys, John m. Hobbs
Abstract/Introduction:
Examples of the five most common flow conditioners, the Zanker, Mitsubishi Heavy Industries Rectifier, etoile, AMCA and tube bundle, have been tested and compared in conditions of fullydeveloped, asymmetric and swirling flow. The configurations chosen as the sources of asymmetry and swirl were a right-angle swept bend and two such bends, adjacent and in mutually perpendicular planes, which are the most common of the disturbed-flow configurations considered by the Standards. The test package comprised a previously-calibrated orifice plate of diameter ratio, 0.8, chosen to present the greatest challenge to the effectiveness of the conditioners. The package was equipped with a single pair of corner pressure taps and four pairs of flange taps. The maximum separation between the disturbances and the conditioners was three pipe diameters and the separation between the conditioners and the orifice plate was varied between 2 and 12 diameters.
Go to Download Page
Email Reference
Document ID:
50CA07A4
Tandem Rotaey Meter Transfer Standard
Author(s): Zane A. Wade
Abstract/Introduction:
This paper describes the application of an interlaboratory calibration technique to the development and testing of a highly accurate and repeatable transfer test standard for domestic gas meter calibration systems. The development of a highly accurate volume standard was culminated in 1981 with the introduction of the Laboratory Piston Prover.(l) This device is comprised of a ball screw driven piston riding in a 300 mm (12 inch) diameter cylinder honed to a tolerance of .0125mm (.0005 inch) on the diameter. A unique oil seal allows the piston to move in the cylinder without contact between them. The volume inside the cylinder is calibrated using a microwave resonant cavity technique.(2) With this procedure, microwaves are injected into the volume via an internal antenna. At certain frequencies a standing wave pattern can be established and these frequencies are a function of the geometry of the cylinder. Under these conditions, the volume can be determined to within 100 ppm (.01%) absolute. Allowing for the uncertainties associated with various transducers, the overall system uncertainty has been established at 0.05% absolute (95% confidence).
Go to Download Page
Email Reference
Document ID:
384FF858
Development And Calibration Of The Boeing 18 kg/s (40 Ibm/sec) Airflow Calibration Transfer Standard
Author(s): Robert L. Stevens
Abstract/Introduction:
A high accuracy, flowmeter calibration transfer standard with an airflow range of 0.0182 (hereafter noted as 1.82E-02) to 18 kg/s (0.04 to 40 Ibm/sec) is described. The transfer standard contains 162 critical flow venturi meters that have a common discharge coefficient curve traceable through a Mass-Time calibration system to the U.S.A. National Bureau of Standards. The transfer standard venturi meters have a continuous curvature entrance and are designed to avoid boundary layer t r a n s i t i o n throughout their operating range. The venturi configuration is described and compared to the familiar circular arc configuration of Smith and Matz.(1) Data are presented which substantiate the method used to obtain a common operating curve. Calibration results from the Mass-Time System are presented and discussed. Discharge coefficient uncertainty is estimated to be 0.07% for individual meters and 0.05% for several meters operating in parallel.
Go to Download Page
Email Reference
Document ID:
2BE61549
Primary Calibration Of The Boeing 18 kg/sec (40 lbm/sec) Airflow Calibration Transfer Standard
Author(s): Walter F. Seidl
Abstract/Introduction:
A calibration was performed by Colorado Engineering Experiment- Station, Inc. (CEESI) on selected Venturis of the Boeing 18 kg/sec (40 Lbm/sec) Airflow Calibration Transfer Standard. The primary flow standard used was a gravimetric standard with a mass flow uncertainty of approximately plus or minus 0.03 percent. An uncertainty of plus or minus 0.05 percent on determination of the discharge coefficient of the Venturis was achieved.
Go to Download Page
Email Reference
Document ID:
F4C2DF4E
Effects Of Mechanical Tolerances On Orifice Meters
Author(s): Raymond G. Teyssandier, Zaki Husain
Abstract/Introduction:
Effects of a number of different mechanical tolerances on the discharge coefficient of an orifice meter were experimentally investigated. Different tolerances investigated were (a) axial location of the upstream and downstream tap in relation to the upstream face of the plate, (b) radial eccentricity of the plate in relation to the azimuthal locations of the flange, pipe and radius taps, (c) plate thickness and bevel angle, and (d) gaps introduced by the ring-type joints. This investigation was limited to determine the effectiveness of the tolerances of the currently accepted standards and provide additional supporting data to the existing database. The results of this study show that the eccentricity tolerance in ISO-5167 is about an order of magnitude tighter than is necessary, while all other parameters are specified with various degrees of adequacy.
Go to Download Page
Email Reference
Document ID:
55E82F29