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Hongjun Sun, Chao Wang
STUDY OF WATER FLOW CALIBRATION FACILITIES WITH MULTI-FUNCTION AND HIGH ACCURACY

The paper describes a water flow calibration facility combined weighing method and master meter method. The flowmeter calibration system aims at obtaining a very high level of accuracy and assurance of product reliability. Moreover, a new method, synchronous pulse counting method, to improve the calibration accuracy and efficiency of master meter method is proposed. Experimental results show that the computer control system is reliable and the accuracy using weight method and master meter method is up to 0.066% and 0.076%, respectively.

Frans van Laak
COMPARATIVE PERFORMANCE EVALUATION BY WIB OF TWO-WIRE AND FOUR-WIRE EMF METERS OF THREE DIFFERENT MAKES

The present comparative performance evaluation has been conducted for the following reasons:
- Two-wire vs. four-wire systems
- Cost
- Accuracy categories of industrial applications
- Aim of project
- Participating manufacturers

Takashi Shimada, Ryouji Doihara, Yoshiya Terao, Masaki Takamoto, Krister Stolt, Anders Andersson
NEW PRIMARY STANDARD FOR HYDROCARBON FLOWMETERS AT NMIJ - INTERNATIONAL COMPARISON BETWEEN NMIJ AND SP

A new primary standard for hydrocarbon flow measurements has been constructed at NMIJ, National Metrology Institute of Japan. The facility is designed for the calibration of hydrocarbon flowmeters in the flow rate range between 3 to 300 m³ / h with an expanded uncertainty better than 0.04 % for volumetric flow rates and 0.03 % for mass flow rates (coverage factor: k = 2). The primary standard applies a static and gravimetric method with flying start and finish. The facility consists of two test rigs with kerosene and light oil as working fluid. The test lines for flowmeters are 50, 100 and 150 mm in diameter, and light oil and kerosene are used as the working fluids. A small volume prover and servo PD meters are used as working standards. This calibration facility has special features that enable highly accurate calibration. The uncertainty of calibration for flowmeters has been roughly estimated. As a result, the estimated uncertainty is shown to be less than the target uncertainty. The dominant sources of combined uncertainty of flow rate are uncertainties in the measurements of the mass of oil in the weighing tank and the density of oil through the flowmeter under test. To verify the performance of this oil calibration facility at NMIJ, an international comparison with SP, Swedish National Testing Research Institute , has been carried out. A screw-type positive displacement flowmeter was selected as the transfer standard and was calibrated at NMIJ and SP . The result shows that the two national standards at the two institutes agree within the quoted expanded uncertainties.

Michael Fuchs, Wolfgang Drahm, Christian Matt, Alfred Wenger
CORIOLIS MASS FLOW METER WITH DIRECT VISCOSITY MEASUREMENT

Coriolis mass flowmeters are widely used in industrial flow measurement. Mass flow is measured directly with very high accuracy (± 0.1% for liquids). These instruments are real multivariable meters, because all meters include direct temperature and density measurements as well. From theses primary measured parameters, , even further variables can be derived; e.g. concentration measurement based on density. The trend in industry shows an increased need for such multivariable instruments, which is due to increased global competition and, thus, requires better process efficiency and stricter quality control. Improving quality and process enables manufacturer to save costs by reducing production time and wasted material. Now, additionally to mass flow, density and temperature measurements, also direct viscosity measurements are successfully integrated into Promass 83 I, which is a single tube Coriolis mass flowmeter with a straight tube. Viscosity is a crucial process variable indicating important fluid properties like consistency, pourability and concentration, which can define the quality of a product. Viscosity can also be an important indicator for problems within a process and, thus, allows the manufacturers to adjust process parameters immediately to prevent a whole batch to be wasted. With these in-line measurements, no time is lost for separate laboratory viscosity measurement.
This paper explains the working principle of the new additional viscosity measurement and demonstrates its opportunities.

Martin Anklin, Alfred Wenger
A NEW SIGHTLY BENT SINGLE TUBE CORIOLIS MASS FLOWMETER FOR CORROSIVE FLUIDS

Commercially available Coriolis mass flowmeters (CMF) show a broad variety of designs, which range from single to dual straight or bent tubes. The new single tube mass flowmeter presented in this paper is slightly bent. The advantage of bent tubes is that thermal stresses are reduced and that the instrument is capable to measure fluids up to 200°C. Furthermore, the slightly bent tube can easily be drained completely. Since the fluid is in contact only with zirconium R60702, mass flow can be determined for a wide variety of corrosive mediums. In particular, zirconium is used for hydro-chloride (HCl) applications, where it does not show corrosion even at high concentrations or at elevated temperatures of HCl.
This paper illustrates the working principle of the new single tube CMF and shows its experimental performance.

Thomas Lederer, Nicolaus Mathies, Jürgen Rose, Dieter Stuck
NEW TEST FACILITY FOR LARGE WATER FLOWRATES UP TO 1000 m³ / h IN A TEMPERATURE RANGE BETWEEN 3 °C AND 90 °C AT PTB - BERLIN

PTB’s Thermal Energy Measurement Section built up a new gravimetric test facility, serving as the national primary standard for volume flowrates of water from 3 m³ / h to 1000 m³ / h and temperatures between 3 °C and 90 °C. The maximum Reynold’s number achieves a value of 5.5 · 106. The test facility can be operated in four different modes to generate the water flow and comprises two independent weighing procedures, to obtain highly-valuable measurement results with an expanded combined uncertainty of 0.04%.
This paper describes the test facility with particular consideration of the technical methods to achieve this high accuracy level.

Lynn A Hendry, John Hemp
THEORY OF A CORIOLIS MASS FLOWMETER INSERTION PROBE

A novel Coriolis mass flowmeter insertion probe concept is described suitable for the measurement of the mass flow of liquids flowing in pipes. It is generally similar to that of the turbine meter insertion probe for volume flow measurement except that the turbine is replaced by a small vibrating aerofoil of elliptical cross-section. The weight vector theory of Coriolis mass flowmeters is applied to predict the approximate sensitivity of the probe. The sensitivity so predicted can be comparable to that of commercial (vibrating tube) Coriolis mass flowmeters so that the signal processing techniques developed for these could be directly used in conjunction with the proposed insertion meter. The dependence of sensitivity on Reynolds number and on liquid density is discussed and a way of removing dependence on liquid density is described.

Mustafa Music
PHASE MODULATION OF THE ULTRASONIC WAVE IN VON KARMAN STREET

It is known that under certain conditions (in certain Reynolds number region) we get double row of staggered vortices in fluid flow behind the bluff body.
Frequency of generated vortices is directly proportional to the average velocity of fluid and that dependence is linear.
Flowmeters based on this phenomenon are known as vortex flowmeters. Origination of vortices causes changes some other parameters such as: pressure, perpendicular forces on fluid flow, etc. Frequency of vortices can be detected by detecting changes of these parameters. Great majority of the vortex flow meters are functioning using this principle.
Mathematical model of the phase modulation of ultrasonic wave that is transmitted normally on the fluid flow behind the bluff body in the region of stable flow will be given in this paper. Phase modulation is directly caused by appearance of vortices in the fluid flow.
We have developed the prototype of ultrasonic vortex flow meter (PVMP 100) DN 100 based on phase ultrasonic modulation, for liquid flow measurement.
Experimental results of testing this prototype vortex meter will be presented in this paper.

Jože Kutin, Ivan Bajsic
THE CHARACTERISTICS OF THE STRAIGHT-TUBE CORIOLIS FLOWMETER FOR DIFFERENT LATERAL VIBRATION MODES

The aim of this theoretical paper is to discuss and compare the measuring characteristics of the Coriolis meter with a straight and slender measuring tube for the lowest three lateral vibration modes. The work is based on an analysis of the analytical approximations of the meter’s characteristics, which are derived from the solutions of a one-dimensional mathematical model. The paper deals separately with the ideal characteristics, the stability-boundary effect, the axial- force effect and the added-masses effect. The influence of the motion sensors’ position is stressed in the presentation of the results.

Gregor Bobovnik, Jože Kutin, Ivan Bajsic
NUMERICAL SIMULATIONS OF THE FLUID FLOW IN THE MEASURING TUBE OF THE CORIOLIS FLOWMETER

The flow of a viscous fluid through a straight measuring tube of a coriolis flowmeter was investigated using numerical simulations. Numerical simulations were performed by the Comet code, which is based on the finite volume method. The simulations were made for various Reynolds numbers at several vibrating frequencies of the measuring tube. The evolution of the axial velocity, a distortion of the axial velocity profiles, a secondary flow in the measuring tube, and a twisting moment acting on the tube’s wall were observed. Values of the twisting moment that acts around the centre of the tube’s length were used to evaluate the performance of the flowmeter at different mass flow rates and various dimensions of the measuring tube.

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