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As a method to mitigate fouling at the venturi flowmeter of pressurized water reactors, electroless nickel-phosphorus (Ni–P) plating and palladium (Pd) plating were conducted on AISI 304L stainless steel specimens and evaluated through a series of performance tests, including static corrosion testing, adhesion testing, and water loop testing using mock-up venturis. As expected from the zeta potentials, no iron oxide particles deposited on the surface of the plated specimens. The Ni-plated specimens exhibited localized corrosion, whereas the minimum oxidation was observed on the Pd-plated specimens. The water loop tests showed consistent results with the static corrosion testing. The adhesion forces after a four-month corrosion test were similar to those before. The overall performance tests indicated that electroless Pd plating on the inner surfaces of venturis could be a viable solution for mitigating fouling in pressurized water reactors.

A multiphase flowmeter (MPFM) is used in the upstream oil and gas industry for continuous, in-line, real-time, oil-gas-water flow measurement without fluid separation. An MPFM typically consists of phase-fraction and velocity measurements. It is desirable to have homogeneous flow at the measurement location so that the phase-fraction measurement is representative. A horizontal blind-tee pipe-section is often installed to homogenize flow in the downstream vertical Venturi-based flowmeters; however, little information is available on the effect of horizontal blind-tee depth (HBD) on flow homogeneity. In addition, the Venturi vertical entrance length (VEL) leading to the Venturi inlet from the horizontal blind-tee outlet is another design parameter that may potentially affect the downstream phase distribution. The phase-fraction measurement principle requires liquid properties. The local liquid richness makes the horizontal blind-tee an ideal location for measuring liquid properties; however, an excessive HBD may affect the reliability of the measurements of liquid properties, because local vortices may degrade liquid measurement representativeness if the local liquid velocity is too low. This study uses a computational fluid dynamics approach to evaluate the effect of HBD and VEL on multiphase flow measurement. The computational results are validated with experimental data collected in a multiphase flow facility.

Development of an accurate and reliable differential pressure flow meters is needed for industry. The relationship between the Reynolds number (Re) and the discharge coefficient (Cd) was investigated using a differential pressure flow meter. Venturi meter is a type of baffle meter, widely used in industry for flow measurement. The ISO standard (ISO-5167-1) provides discharge coefficient values for classic Venturi tubes in turbulent flow with Reynolds number values above 2x105. This study shows that various discharge coefficient decrease rapidly and constant discharge coefficient values vary with meter design. The main focus of this study is to compare experimental results with theoretical predictions and estimate the optimal value of thevmeter discharge coefficient at various flow rates. The experimental results showed that the optimal value of the venturi tube discharge coefficient of about 0.983 was obtained.

According to the working process of dynamic throttling element flowmeter, the Reynolds number keeps constant when the flow is steady. The way to change the pressure drop is to change the local pressure loss. Based on the Fluent software, analyze how the structure parameters of venturi tube affect pressure drop. With the completion of flowmeter prototype, test the dynamic throttling element by using a kind of binary flow calibration platform. According to the test result, figure out that the optimization can perfectly meet the real flowing condition.

Within the framework of the ITER project, CEA/SBT is in charge of the design, manufacturing and delivery of 277 Venturi flowmeters. The latter were developed for either the control of the supercritical helium flow in the magnets at cryogenic temperature (4.5 K) or the operation of the current leads at room temperature. Depending on the temperature, the values of the Reynolds number in the Venturi tubes are significantly higher or lower than those specified in the standard NF EN ISO 5167-4 regarding the design of Venturi flowmeters. An experimental determination of the flowmeter coefficient was therefore required. Due to the large number of flowmeters, a manufacturing strategy was developed in order to obtain a reproducible behaviour. This strategy was validated by the experimental results obtained at room and cryogenic temperature.

Although accurate flow measurement is a requirement in many applications, flowmeters are often installed in unfavorable conditions. Any time a flowmeter is installed close to a flow disturbance, such as a pipe fitting or a valve, the installation should be investigated to ensure there will be no negative effects on the meter’s performance. This study investigated the use of computational fluid dynamics (CFD) coupled with laboratory data to determine the effects that sudden changes in pipe diameter can have on the discharge coefficients of Venturi flowmeters. The study determined how accurately CFD can match laboratory data, then used CFD to determine the distance needed between a sudden change in diameter and a Venturi flowmeter so that the meter is no longer affected by the disturbance. The results show that CFD can be an effective tool for investigating installation effects for flowmeters.

The measurement of coolant flow is important operational parameter for reliable operation of cryogenic system with superconducting magnets or cavities as well as for the system diagnostics in case of non-steady-state operation, e.g. during cool-down/warm-up or other transients. Proper flowmeter is chosen according to the different parameters, e.g. turn-down, operating temperature range, leak-tightness, pressure losses, long-term stability, etc. For helium cryogenics, the Venturi tube or Orifice, as well as Coriolis flow meters are often applied. For the present time, the orifices are usually used due to their simplicity and low costs, however, low turn-down range, large pressure drop, restriction of flow area, susceptibility to thermoacoustic oscillations limit their useful operation range. Operational characteristics of Venturi tubes is substantially improved in comparison to orifices, however, relative high costs and susceptibility to thermoacoustic oscillations still limit their application to special cases. The Coriolis flow meters do not have typical drawbacks of Venturi tube and orifices, however long-term stability over many years was not demonstrated yet. This paper describes the long-term behaviour of Coriolis flow meters after many years of operation at AMTF and XMTS facilities.

Accurate measurements of the helium flowrate and of the temperature of the ITER magnets is of fundamental importance to make sure that the magnets operate under well controlled and reliable conditions, and to allow suitable helium flow distribution in the magnets through the helium piping. Therefore, the temperature and flow rate measurements shall be reliable and accurate. In this paper, we present the thermometric chains as well as the venturi flow meters installed in the ITER magnets and their helium piping. The presented thermometric block design is based on the design developed by CERN for the LHC, which has been further optimized via thermal simulations carried out by CEA. The electronic part of the thermometric chain was entirely developed by the CEA and will be presented in detail: it is based on a lock-in measurement and small signal amplification, and also provides a web interface and software to an industrial PLC. This measuring device provides a reliable, accurate, electromagnetically immune, and fast (up to 100 Hz bandwidth) system for resistive temperature sensors between a few ohms to 100 k . The flowmeters (venturi type) which make up part of the helium mass flow measurement chain have been completely designed, and manufacturing is on-going. The behaviour of the helium gas has been studied in detailed thanks to ANSYS CFX software in order to obtain the same differential pressure for all types of flowmeters. Measurement uncertainties have been estimated and the influence of input parameters has been studied. Mechanical calculations have been performed to guarantee the mechanical strength of the venturis required for pressure equipment operating in nuclear environment. In order to complete the helium mass flow measurement chain, different technologies of absolute and differential pressure sensors have been tested in an applied magnetic field to identify equipment compatible with the ITER environment.

In the framework of the ITER project, the CEA-SBT has been contracted to supply 277 venturi tube flowmeters to measure the distribution of helium in the superconducting magnets of the ITER tokamak. Six sizes of venturi tube have been designed so as to span a measurable helium flowrate range from 0.1 g s to 400g s. They operate, in nominal conditions, either at 4K or at 300K, and in a nuclear and magnetic environment. Due to the cryogenic conditions and the large number of venturi tubes to be supplied, an individual calibration of each venturi tube would be too expensive and time consuming. Studies have been performed to produce a design which will offer high repeatability in manufacture, reduce the geometrical uncertainties and improve the final helium flowrate measurement accuracy. On the instrumentation side, technologies for differential and absolute pressure transducers able to operate in applied magnetic fields need to be identified and validated. The complete helium mass flow measurement chain will be qualified in four test benches: - A helium loop at room temperature to insure the qualification of a statistically relevant number of venturi tubes operating at 300K.- A supercritical helium loop for the qualification of venturi tubes operating at cryogenic temperature (a modification to the HELIOS test bench). - A dedicated vacuum vessel to check the helium leak tightness of all the venturi tubes. - A magnetic test bench to qualify different technologies of pressure transducer in applied magnetic fields up to 100mT.

Superconducting magnets of Steady-state Superconducting Tokamak-1 (SST-1) are cooled by Supercritical helium at 4.5 K and 0.4 MPa. Two types of Venturi meters (VM) are being used for measuring helium mass flow rates in these magnets. Signal conditioning for temperature, absolute pressure and differential pressure sensors and a suitable data acquisition system has also been developed for these flow meters. These flow meters were extensively qualified during individual coil test campaigns of SST-1 TF coils. Mass flow and pressure signal behavior during quench events of TF coil tests were analyzed and a quench detection system using these signals has been proposed for TF coils. This secondary quench detection methodology and its hardware development are discussed in this paper. This paper also describes the VM design, fabrication, installation and the flow measurement system.