M. Pusayatanont, P. J. Unsworth, E. H. Higham
This paper presents a new technique for measuring the volumetric flow rates of each phase in a two- phase gas-in-liquid flow regime, by analysis of the sensor signal from a conventional vortex flowmeter. The vortex flowmeter has become established throughout the process industry for the measurement of both liquid and gas flows, principally because of its wide rangeability, coupled with a nearly linear relationship between the vortex shedding frequency and volumetric flow rate, plus the fact that it has no moving parts which are liable to deteriorate in service. In recent years, the...
S. Al-lababidi, M. L. Sanderson
A series of experiments has been undertaken to investigate the behaviour and the performance of a clamp-on transit-time ultrasonic flowmeter in two-phase air/water flow. The results show the performance of the liquid ultrasonic meter to be seriously affected by the presence of free gas in a manner that is dependent on the actual flowrate of the gas and the flow regime. The data presented here covers water/air flow under slug flow regime and an evaluation of transit-time ultrasonic meter and its suitability for two-phase flow measurements. The factors affecting performance are discussed and a...
J.-F. March
For measurements of thermal energy, produced by thermal solar systems, heat meters, installed in collector circuits of solar systems, must be qualified for the most used propylene glycol-water-mixtures as heat conveying liquid. In the project, sponsored by the “Deutsche Bundesstiftung Umwelt (DBU)” and the heat meter industry, the accuracy of several types of flow sensors at nominal flow rates between 0.6 m³/h and 1.5 m³/h had been investigated using propylene glycol-water-mixtures.
Grzegorz L. Pankanin, Jerzy Berlinski, Ryszard Chmielewski
The work refers to the vortex flow meter optimisation. Searching of the optimal geometry of the meter became the fundamental task for designers. For many years their attention has been focused mainly on the bluff body as well as on the sensor designing. Numerous experiments made by authors of the paper confirm that not only the bluff body shape but also geometry of the duct impacts the vortices development. Duct walls stabilize the vortex shedding and its development process. Hence the conception of flow duct tapering in the vortices development zone. On the basis of the numerical simulation...
M. L. Sanderson, R. H. Al-Rabeh
A method is reported here for the ultrasonic measurement of flow in boiler super-heater tubes. The tubes are in a tube bank formation running at high temperature (typically 300°C) and pressure (typically 100bar). To enhance heat transfer, the tubes in this application are ribbed internally with thick helical ribs. Further, all measurements have to be made on one side of the tube bank to avoid direct radiation on the fire side. Conventional ultrasound methods are difficult to apply in these conditions. The combination of thick steel walls, internal ribbing and the substantial temperature and...
Rainer Engel, Hans-Joachim Baade
PTB’s new "Hydrodynamic Test Field", which represents a high-accuracy water flow calibration facility, will serve as the national primary standard for flow measurands: volumetric and mass flow rate, respectively, and total flow measurement, i.e. the quantity of fluid (volume or mass) passing a flowmeter. As most accuracy determining component parts, it comprises three different-size dual-balance gravimetric reference systems: 300 kg, 3 tons and 30 tons. This type of gravimetric references were realized as a combination of a strain gauge based and electromagnetic force-compensation load cell...
Esa Luntta, Harri Nystedt, Jouko Halttunen, Juha Kortelainen
Electromagnetic flowmeters are today practically the only meter type used in the measurement of pulp flows in paper mills. Usually, these meters have the required accuracy (or at least they are believed to have), the price of them is reasonable, and they are almost maintenance-free. However, electromagnetic flowmeters are usually calibrated in water flow and the effect of the change of the flowing medium to pulp on the accuracy has been investigated rather little. The possible error sources in pulp flow measurements can be for example non-uniformity of conductivity or air content of pulp...
Ryouji Doihara, Yoshiya Terao, Masaki Takamoto
A new design concept for improving the sensitivity of a Coriolis flowmeter is proposed. The differences between the developed flowmeter and current commercial products lie in adoption of acceleration sensors and reinforcement frames. These features impart an interesting characteristic: sensitivity improves with increasing drive frequency. A flow tube has been fabricated on the basis of the new design concept, and subjected to basic experiments in order to confirm the characteristics of the measurement system. Although some problems still remain, the characteristics have been partially...
Helmut Többen
The measuring volume of a pipe prover used as a volumetric standard measuring device in the hydrodynamic test field was calibrated by a geometrical measuring method, having been implemented for the first time. Using incremental length measuring devices for the axial and lateral direction a more precise characte rization of the volume is feasible.
Yeh-Chan Ahn, Byung Do Oh, Moo Hwan Kim
The theory for the current-sensing electromagnetic flowmeter was newly developed. The current-sensing flowmeter has a high temporal resolution so that it can be applied to measure the flows with fast transients like two-phase flow. The signal prediction and the calibration of the current-sensing flowmeter in two-phase flow and the measuring of the characteristics of two-phase flow are the major concerns. To do this, using a finite difference method, the three-dimensional virtual potential distributions for the electrodes of finite size were calculated for single-phase flow, annular flow and...