G. Kok, N. Pelevic, A. Chiribiri, X. Milidonis, M. Nazir, M. Capstick, S. Drost, C. Poelma, T. Schaeffter
In the medical sector, various imaging methodologies or modalities (e.g. MRI, PET, CT) are used to assess the health of various parts of the bodies of patients. One such investigation is the blood flow or perfusion of the heart muscle, expressed as the (blood) flow rate normalized by the mass of the volume of interest, with unit mL/min/g. Currently there is no physical flow standard for the assessment and validation of myocardial perfusion imaging methodologies, resulting in a large proportion of medical diagnoses being inaccurate and highly dependent on the scanner type, software used and...
S. Wada, N. Furuichi, H. Hamada, T. Akama, T. Yamaguchi, S. Suzuki, S. Takatsuka
This paper presents experimental measurements using the clamp-on ultrasonic flowmeter. To obtain an uncertainty of flow rate measurement using the clamp-on ultrasonic flowmeter, experiments are carried out at the national standard calibration facility of water flow rate in Japan (the National Institute of Advanced Industrial Science and Technology, National Metrology Institute of Japan). Flow rate given by the clamp-on ultrasonic flowmeter is compared with the static gravimetric method using a tank system weighing 50 t. The uncertainty of the reference flow rate given by the 50 t weighing...
I. B. S. Bispo, L. C. Pacifico, W. O. Chaves, N. M. Taira, P. J. S. Jabardo
The Cole type Pitot tubes (Pitot-Cole tubes) are widely used by water utility companies to map fluid flow velocity profile and thus measure the flow rate in pipelines. This technique is mainly used for on-site calibration of other kind of flow meters, such as electromagnetic or ultrasonic, particularly when removing the meter from the pipeline is somehow not feasible. Therefore, when using Pitot-Cole tubes for those purposes, the determination of the calibration coefficient (Cd) and its associated uncertainty contributes significantly to the results of such measurements. This paper presents...
A. N. Johnson, I. I. Shinder, J. B. Filla, J. T. Boyd, R. Bryant, M. R. Moldover, T. D. Martz
Exhaust flows from coal-fired stacks are determined by measuring the flue gas velocity at prescribed points in the stack cross section. During the last 30+ years these velocity measurements have been made predominantly using Stype pitot probes. These probes are robust and inexpensive; however, S-probes measure only two components of the velocity vector and can give biased results if the stack flow has significant yaw and pitch angles. Furthermore, Sprobe measurements are time intensive, requiring probe rotation (or nulling) at each traverse point to find the yaw angle. The only...
N. Pedisius, A. Bertasiene
Information about the airflow development in pipes in the entrance region is still not thoroughly investigated due to the complexity and restricted access for experiments. However, the reproduction of air velocity values, as well as calibration of the devices, is usually made in free streams from the nozzles or in the entrance region of the channels (pipes). In this study, different flow regimes have been investigated using different air velocity measurement methods for mean velocity to define. Experimental and numerical results in the entrance region of the pipe and in the test chamber of...
Arnthor Gunnarsson, Jos van der Grinten, Mijndert van der Beek, Bodo Mickan
The EuReGa members that use a Piston Prover as a primary calibration device (PTB, VSL and FORCE Technology) performed an intercomparison in 2018-2019. This paper will describe the Piston Provers used in the intercomparison after which the intercomparison results and their implication will be presented. Degree of equivalence has been determined on multiple occasions in the past between the participants. What distinguishes this intercomparison from others is that it is performed with Piston Provers, which is the starting point in the respective participants traceability systems. This means...
J. D. Wright, S. D. Sheckels, J. T. Boyd
The custody transfer of petroleum worth $1 x 1012 / year is traced to the volume delivered from provers and liquid test measures. Mistakes as small as 0.02 % in a custody meter calibration can lead to multi-million dollar corrections in bills. NIST presently uses the direct weighing method to measure the volume delivered from a test measure, by weighing (on a calibrated balance) the test measure when it is full of pure water and again after it has been drained. Recently, NIST reduced the uncertainty of its calibrations of volumes between 3.8 L and 40 L by constructing an automated...
J. D. Wright, J. W. Schmidt
New applications in biology, medicine, and manufacturing require reliable measurements of liquid flows smaller than 100 μL/min. NIST addressed this requirement by improving the reliability and ease of use of NIST’s Dynamic Gravimetric Micro-Flow Standard. The meter under test is now connected to the weighing beaker by a liquid bridge that reduces variations in parasitic surface tension forces as the level of liquid in the collection beaker rises. We describe other improvements to NIST’s standard (e.g. pipette positioning and evaporation reduction) and provide an uncertainty analysis for the...
Chuanbo Zheng, Xingchuan Chen, Yiwen Liu, Wei Han, Zhe Liu
Based on the different ways of data collection which adopted by the current domestic natural gas flow metering station, this paper first analyzes the theoretically applicability and limitations for two kinds of data collection methods: instantaneous flow and cumulative flow, and obtains the relation and distinction between these two ways. Then, the flow-meters with different diameters are actual tested in two data acquisition ways, instantaneous flow and cumulative flow, which performed by the work level standard device of substation in Guangzhou. The results show that the different methods...
Qingqiang Hou, Meng Yang, W. Han, J. H. Niu, K. C. Wu
When the CFVN calibration is carried out, the inlet temperature measurement of the CFVN is detailed described in both “ISO 9300:2005 Measurement of gas flow by means of critical flow Venturi nozzles” and “JJG 620-2008 Critical Flow Venturi Nozzle”. But in some cases, the sensing element can not be strictly confirmed to the requirement for some reasons. To explore the influence of the inlet temperature measurement, two different kinds of installation are presented in this paper. Differences between the two installations are the diameter of the sensing element and the location of the sensing...