Nilson Massami Taira, Kazuto Kawakita, Valmir Ruiz
Accurate measurement of water flow rates in large diameter pipelines is a challenge for water companies that need to produce, transport and distribute increasing quantities of water. To a large extent, this challenge results from the impossibility of recalibration of the flow meters within the periodicity established in the metrological regulations since the removal of a large flow meter from its site of operation in the field and its dispatch to a calibration laboratory is in most cases technically and economically impracticable. As a result of this scenario, the article presents the...
W. Kang, D. T. Nguyen, Y.-M. Choi, S.-H. Lee
In the monitoring of greenhouse gas emission from industrial smoke-stacks, the most common device used to measure the stack gas velocity is the S-type Pitot tube in South Korea, which is used to estimate the volumetric flow rate by what is termed the Continuous Emission Monitoring System (CEMS). The S-type Pitot tube installed in the stack is inevitably affected during velocity measurements by velocity changes, yaw and pitch angle misalignments due to the harsh environments. Various geometries of the S-type Pitot tube can affect the characteristics of the S-type Pitot tube coefficients,...
Chaojian Tao, Youyi Pan, Liqiong Huang, Yong Wang, Shouyang Zhang, Guofen Yang, Zubao Chen
To study a gas standard facility by master meter method, a master meter flow range is 10 to 250 m³/h, DN80. With one large-capacity temperature chamber, and the meter under test (MUT) places in the temperature chamber. The temperature chamber can be adjusted to a temperature range of -25 to 55 °C, and the temperature is stable when the test flow reaches a maximum of 250 m³/h. The master meter is placed in a room temperature environment, and a heat exchange is installed between the master meter and the MUT.The facility can be used to calibrate increasingly growing gas flow meters such as gas...
F. Ogheard, P. Cassette, A. W.Boudaoud
Radiopharmaceuticals used in nuclear medicine for therapy or diagnosis (molecular imaging, PETscan, scintigraphy) are characterized in terms of volume activity before injection to patients. The current measurement process relies on dose calibrators which have to be calibrated by transfer standards, traceable to primary standards. For very short half-life radionuclides (few minutes), the metrological traceability can only be assured through an on-site calibration with primary standards. However, until now, there is no primary system for the direct measurement of such high activity radioactive...
A. Stetsenko, V. Naumenko
With the increase in the requirements for the accuracy of measurement in the commercial accounting of natural gas, the issue of initial calibration and periodic verification of measuring instruments in conditions as close as possible to actual working conditions is relevant and commonly discussed among professionals. This issue also applies to ultrasonic gas meters. Despite the general tendency to calibrate (verify) ultrasonic gas meters at operating conditions, this requirement is not always appropriate. First of all, this is due to the high cost of calibration services and the...
Yu Gu, HanSheng Ye, ZhongJun Han, Feng Chao
Pitot tube has the advantages of small pressure loss, cost economical, compact size, easy to cary, install and measure., which make It suitable for the flow measurement of medium and large d ameter pipes, and flow velocity and velocity distribution measurement at any point in air duct, water pipe and mine. However, when measuring the mixed phase fluid of gas and liquid, the pitot tube will have abnormal fluctuations in the flow measurement with the passage of time, and the measurement result would be far from the actual flow rate. Gas-liquid mixed phase fluid is widely used in industrial...
Peijuan Cao, Chao Wang, Chunhui Li, Hongbing Ding
To improve the measurement accuracy of sonic nozzle, the theoretical analysis and waviness profile measurement for the discharge coefficient of sonic nozzles were conducted. The theoretical discharge coefficient used a correlation model that accounts for both viscous effects due to the boundary layer along the nozzle wall (Cd,1), and the axisymmetric sonic line in the core region (Cd,2). Firstly, the inner surface coordinates of one sonic nozzle with nominal throat diameter of 7.45 mm were measured by CMM of NIM, including the throat diameter d and curvature radius Rc. The curve profile,...
W. L. Chen, J. Mu
An air test line of 50mm diameter was used in experiments covering two kinds of straight pipe length, and the numerical simulation results of vortex shedding frequency, which originated from the ANSYS FLUENT analysis results, were proved to be highly consistent with the experimental results. Based on this comparison, flow field simulation studies, including 13 pipe conditions, were carried out to establish the effect of upstream and downstream elbow fittings on the performance of the vortex flowmeter. The results indicated that the influences of the upstream straight pipe length were more...
Xiao-Zhang ZHANG
This paper reviews main previous works on the models of Coriolis flowmeter behaviour in two-phase flow. By experiment of bubble flow in vertical pipe with/without external vibration, some useful phenomena were observed. A general solution was obtained to the dynamic equation of a bubble motion. Some comments were given to the prediction of measurement errors by Coriolis flowmeters. Main points are: In most cases bubble shape is not sphere, but flat. Flat bubbles will be easy to move along a non-straight orbit, this causes transverse motion of the bubble. The transverse motion of bubbles are...
F. Lu, J. M. Zhang, Y. M. Shen
For the butterfly flow-regulating valve commonly used in the variable head flow standard device, the threedimensional flow field in the valve body was simulated during the flow regulating process by CFD dynamic mesh technology. The flow field changes with cloud maps in the internal and downstream piping of the valve body under several operating conditions of 10°, 30°, 45°, 60°and 90°opening was proposed in the condition of constant water head. The simulation results also show that there are two opposite vortices in the flow field downstream of the valve body at 10° and 30° opening, and the...