Development and evaluation of the calibration facility for high-pressure hydrogen gas flow meters

The calibration facility with the multi-nozzle calibrator was developed for the calibration of flow meters to be used with high-pressure, high-flow-rate hydrogen gas. The critical nozzles installed in the multi-nozzle calibrator were calibrated with traceability to the national standard. The relative standard uncertainty of the mass flow rates produced from the calibration facility is 0.09% when the flow rate is between 150 g/min and 550 g/min. In this study, the Coriolis flow meter was calibrated for a pressure range of 15–35 MPa. The relative standard uncertainty of the flow rates obtained from the Coriolis flow meter was 0.44% for the case of the worst fluctuations in the output of the flow meter; based on the calibration curve, this is 0.91%. The present result shows that there is a maximum 3% difference between the output of the Coriolis flow meter and the mass flow rates of the multi-nozzle calibrator, even though the Coriolis flow meter was calibrated using water. Therefore, for the development of a calibration facility that can calibrate a flow meter under the same conditions as those encountered in actual use, it will be important to develop a new flow meter.     

Development of a device for the measurement of thermal and fluid flow properties of heat exchanger materials

As yet, no standard equipment exists for the measurement of heat transfer through porous materials, such as metal foams (metals with a high volume fraction of porosity). Most research in this area has been carried out using bespoke test rigs. Here the creation of a test rig specifically developed for the measurement of the heat transfer of metal foams is reported. This method has been applied to laboratory made samples processed by replication and examples of commercially available aluminium foams (Duocel and Corevo), and should be suitable for the testing of all materials with comparable permeability. As this equipment is new and unique, the design will be discussed in detail, along with the various tests that were performed to ensure reliability and consistency with other methods and published data.     

PLC在原油计量和标定装置中的应用

本文介绍一种流量计标定控制系统,文中详细介绍了其工作原理及控制系统的软硬件结构。     

Calibration procedures and uncertainty analysis for a thermal mass gas flowmeter of a new generation

This paper deals with the differences between traditional and new technology gas meters, and focuses specifically on the calibration procedure and uncertainty evaluation of CTTMFs (Capillary Type Thermal Mass Flow Meter). In particular, measurements performed on a sample set of commercial CTTMFs for natural gas in domestic/residential (G4) applications allowed to evaluate the modifications to calibration procedures required by the new generation, digital, gas flow meters. Indeed, traditionally natural gas is metered by means of volumetric measurement techniques, while the modern, static gas flow meters (thermal and ultrasonic ones) are based on electronic flow sensors. This implies that the gas volume through the meter is measured by sampling the flow rate at selected time points and integrating the flow rate in time. The measurement time becomes therefore an important parameter, thus requiring a thorough rethinking of the calibration procedure. In order to analyse the effects of the various parameters, a series of ad-hoc calibrations were performed. Specifically, one set of calibrations was performed with constant totalized volume, while the other required a constant measurement time. In order to highlight the novelties that will have to be implemented in ordinary calibration procedures to get the best of the new technologies, the two procedures as performed on a sample set CTTMFs will be compared; the theoretical (generic) evaluation of the associated uncertainty will also be presented. Measurements were carried out at the test facility of INRIM, the Italian National Metrology Institute.     

Automated control of the velocity of in-tube diagnostic tools for main gas pipelines: I. Development,design, and operating principle of a bypass device

The study considers the development, design, and operating principle of a bypass device integrated into existing in-tube diagnostic tools. The bypass device is designed for automated control of the velocity of in-tube pig flaw detectors in main gas pipelines. Equipment of in-tube diagnostic tools with an automated-control system for the velocity provides performance of in-tube inspection without decreasing gas transportation. This facilitates the flaw detection of main pipelines substantially and makes a dispatcher of a gas-compressor station free of controlling the velocity of passage of in-tube diagnostic tools. The results of assembling a bypass device used for automated control of the velocity of in-tube diagnostic tools for main gas pipelines are considered. Arrangement of the bypass device in existing diagnostic tools for nondestructive testing is based on the experience of development, design, and exploitation of pig flaw detectors, which make it possible to locate the elements of the bypass device without any substantial restructuring of the pig flaw detectors.     

Development of a new system for measuring the swirl ratio of an engine cylinder head under an unsteady flow condition

A new impulse-type swirl meter that measures the swirl ratio (R_s) and flow coefficient (C_fmean) during an intake air process for the intake port of an engine cylinder head under unsteady flow conditions was developed. The camshaft of the cylinder head was directly rotated by a step motor, allowing the valve lift to be adjusted automatically with the camshaft profile in the newly developed swirl measurement system. The measurements of the swirl ratio and flow coefficient were automated using a FPGA-DAQ board and a computer. The rotational speeds of the camshaft were held constant at steps of 90, 120, 150, 180 and 210 rpm during the measurement. As the camshaft rotation speed increased, the values of R_s tended to decrease while those of C_fmean tended to increase, implying that R_s and C_fmean depend on the engine speed. These results should be considered in the design of an intake port. With the newly developed swirl measurement system, it is possible to measure R_s and C_fmean repeatedly in a very short time. The repetitive measurement results of R_s and C_fmean were statistically processed. Through an uncertainty analysis, the values of the upper and lower bounds of R_s and C_fmean can be calculated for each camshaft rotation speed.

     

三环减速器的工作原理与功率流分析

通过对三环减速器高速轴曲柄转矩变化规律的分析，研究了三相并列平行曲柄输入机构克：服死点、实现连续运动的工作原理，并对减速器中的功率流动和偏心套微动磨损现象进行了探讨。     

减压阀（站）在消除长输管道不满流中的应用

大落差线路存在剩余能量是产生不满流的根本原因，它可能引发水击、振动，气蚀，产生气液混合物以及增大多种液体顺序输送时的混输量等一系列问题，设置减压阀（站）可有效地消除大落差线路的不满流，是一种合理的处置技术。     

LDA-measurements in natural gas high-pressure pipelines for the testing of turbine gas meters

In industrial gas volume measurement, the reliable, precise and economically efficient determination of gas quantities by measurement is of utmost importance. Standby meter sections, Z-connection and permanent series connection of two gas meters of different designs are state of the art [Schmittner, D., The importance of the accuracy of measurement for industrial gas measurements. 3R International, Vol. 30, No. 6–7, 1991, pp. 338–343 (in German)]. The permanent or temporary series connection for the comparison and test section makes expenses for a second complete measuring device necessary. An alternative at present is the dismounting of the gas meter and the check test in an appropriate high-pressure test facility. A test according to requirements, using a non-interacting measuring instrument which should be transportable, if possible, and usable with other gas meters can be a bridge between these two possibilities. To prove this, measurements with an LDA system were carried out in a natural gas high-pressure pipeline upstream of a turbine gas meter. After extensive profile and single-point measurements have been made it can be said that this test by the single-point method is feasible with an uncertainty of ≤ ± 0.5%, providing defined prerequisites are met.     

Development of a low cost portable pressure measurement system using for garment design

Pressure comfort is an important part of garment comfort evaluation, in this paper, a low cost portable pressure measurement system (PPMS) are developed for measuring pressure distribution on garment. Three sets of different size knitted garments are fabricated for investigating the pressure distribution on a mannequin and on young female volunteers. Experimental results show curvature radius of points on the mannequin are smaller, pressures are larger which is consistent with the pressure calculation equation. Pressure distribution state on human body is different from that on mannequin due to size and shape difference even if the same garments were utilized. Dynamic pressure measurement on human body shows the pressure variations on points of human body. However, the static and dynamic pressure data can be utilized for improving quality of garments and helping design of garments.     

Experimental verification of numerical predictions for the optimum plunger speed in the slow phase of a high-pressure die casting machine

An experimental study of the optimum maximum plunger speed in the slow phase of a high-pressure die casting machine with horizontal cold chamber is presented. A special apparatus that uses a photoelectric sensor to determine the instant at which the working fluid reaches the runner was developed and installed in the injection chamber. The measured volumes of air remaining in the chamber at this instant for various maximum plunger speeds were compared with those predicted by a three-dimensional numerical model based on a finite element formulation and the volume of fluid method for treating the free surface. Very good agreement was found between experimental and numerical results, except for maximum plunger speeds higher than the optimal, for which very complex fluid flow phenomena (that would require a more detailed numerical analysis of the air entrapment mechanisms) tend to be produced. The optimum maximum plunger speed at which the measured volume of trapped air is minimum was found to be very close to that predicted numerically.     

Development of a turbine meter for two-phase flow measurement in vertical pipes

The performance of a turbine meter in two-phase (water/air) flow in a vertical pipe is assessed. If the single phase (water) meter factor is used in two-phase flow, the total (water and air) flowrate is found to be underpredicted. The error can be as much as 12.5% at a void fraction of 25%. A technique for using measurements of the fluctuations in the turbine meter rotor velocity to determine void fraction (= air flowrate/total flowrate) is described. A single meter is then used to measure, using this technique, both the water flowrate to an accuracy of ± 2% and void fraction to an accuracy of ±0.02.     

Development and validation of a new reference cylindrical gear for pitch measurement

A new type of master gear, the Gauge Block Gear (GBG), was developed for the performance verification of coordinate measuring machines (CMMs), for the specific task of pitch and chordal tooth thickness measurement. Its main characteristic is the replacement of the teeth with gauge blocks to achieve direct traceability of the chordal tooth thickness. Mathematical models for the geometrical definition of cylindrical gears with involute toothing, data evaluation, and assessment of the task-related uncertainty, were formulated, and measuring strategies for CMMs were designed and implemented. The GBG was calibrated using the swing round method, and measurement uncertainties on chordal tooth thickness and total pitch deviation F_p were determined to be 0.9 μm and 1.4 μm, respectively. Assembly stability and flexibility of the artefact were verified with measurements performed on a CMM provided with general purpose software, one with dedicated gear measuring software, a form tester, and a conventional gear measuring center. Results confirm the correctness of the mathematical models developed to analyze CMM results as well as their compatibility with existing approaches. The Gauge Block Gear provides, therefore, for direct traceability of the chordal tooth thickness and allows the definition of the task-specific uncertainty of pitch and tooth thickness measurements of cylindrical gears as basis for the assessment of the metrological capability of measuring machines.     

An extension of laser-interferometric CT measurement to unsteady shock waves and 3D flow around a columnar object

The 3D laser-interferometric CT measurement of the unsteady flow field induced by shock wave discharging from a circular nozzle next to a short columnar object in a shock tube experiment is presented as an extension of previous work of 3D measurement of open flow field. The 3D density distribution around the object is reconstructed with FBP (filtered back projection) and MLEM (maximum likelihood expectation maximization) algorithm from the incomplete projection data caused by the obstruction of the observation light for interferometry with an object in a test section. The 3D density-gradient distributions are also evaluated from the resultant 3D density distribution, we demonstrate that laser-interferometric CT measurement of interaction field of shock waves and an object come to sight.     

Development of a vision based deflection measurement system and its accuracy assessment

A vision-based method for measuring civil engineering constructions’ in-plane deflection is presented in this paper. Displacements of points are computed by means of digital image correlation. The application of homography mapping enables the deflection field to be computed from two images of the structure acquired from two different points in space. The verification of the developed system is performed using the coordinate measuring technique. Results of the beam deflection obtained from the developed vision system and Laser Tracker device are compared. Moreover, the uncertainty of the system is evaluated and possibilities for its improvement discussed.     

A new modification of the radiotracer balance method for open channel flow measurement

Open channel flow rate was determined by using the radiotracer balance method (RBM). The magnitude of errors arising from the scattering was investigated in the study. An open channel experimental system was set up in the laboratory. For the experiments Na-24 was used, which was irradiated in the TRIGA Mark-II Training and Research Reactor. Error evaluation observed whether the scattering effect with modification of the calibration factor could improve the results.     

Development of a transfer standard with sonic Venturi nozzles for small mass flow rates of gases

We have developed a transfer standard system with sonic Venturi nozzles for small mass flow rates of gases. The system is composed of a newly developed automatic pressure controller, two pressure sensors and one temperature sensor to measure the flow conditions in the upstream and downstream sides of a nozzle. The whole system is packed in a portable aluminum trunk. The data are sent to a laptop computer, and the results are displayed on the screen and are written to files. The system can calibrate a flow meter in the flow rate range from 10 mg/min to 100 g/min using ten different sonic Venturi nozzles with the expanded standard uncertainty (k=2) being less than 0.2% for nitrogen. Examples of mass flow controller calibrations are given.     

Pressure sensor matrix for indirect measurement of grip and push forces exerted on a handle

To date, a large part of workers is exposed to vibrations (23% in Europe) which can negatively impact on their health. This work discusses the importance of measuring grip and push forces in the context of hand-arm vibration tests, bearing in mind the state-of-art of current standards. It proposes a method for indirect measurement of coupling forces using a matrix of polymeric pressure capacitive sensors and discusses the model used for defining these quantities. The matrix of pressure sensors is wrapped around the tool handle and the acting forces, exchanged with the handle, are derived from the pressure values measured by the matrix. Calibration is presented and the effect of curvature is discussed. The work continues with the experimental validation of the model proposed for push force measurements carried out through lifting tests using known masses with a cylindrical handle. An experimental correction coefficient is defined in correlation to the type of grip. The method for measuring the push force, thus corrected, is assessed by means of push force tests on an instrumented handle. Finally the experimental data are analysed in order to assess the uncertainty of the proposed method for measuring the push force, highlighting the contribution of the different sources of uncertainty. The proposed measurement method allows to measure the push and the grip force (known influencing quantities for the measurement of the hand-arm vibration) during tool test and without modifying the handles.     

Three-dimensional Doppler Global Velocimetry in the flow of a fuel spray nozzle and in the wake region of a car

A Doppler Global Velocimetry system optimised for time averaged three component velocity measurements was designed and set-up. The first application of the system was the investigation of the flow field of a swirl spray nozzle in a cylindrical casing. Because of the axial symmetry of the mechanical set-up it was possible to measure the planar distribution of all three velocity components of the highly three-dimensional flow with just one optical arrangement. The flow field in the whole volume of the combustor was measured in only 10 min. This is extremely fast and demonstrates the most important property of the new system.The DGV system was also applied to investigate the wake region of a car model in a wind tunnel. An arrangement with three light sheets was chosen. The 3D-DGV results are in good agreement with 3D-LDA measurements of the same flow.     

Analysis of pressure distribution for the various gas flow vacuum system in the range from 1 Pa to 133 Pa

The measurement and control of gas flow are critical in many manufacturing processes. Semiconductor manufacturers, in particular, require a number of different process gases for etching, deposition, oxidation, doping and inerting applications. In many of these, as well as other industrial and research processes including measurement of partial pressures with residual gas analyzers (RGAs), calibration of vacuum gauges, and conductance of a conductance-reducer , accurate measurement and stability of the gas pressure within the reaction vacuum chamber is essential. In the present work, pressure distribution in the chamber of a newly developed flow control system was investigated for three gases (Ar, N₂, and He) range from 1 Pa to 133 Pa. For all the gases, the relative deviations in pressure distribution near the gas inlet and outlet were in the range of −1.3% and 1.2% respectively.