Results Of Flow Rate Measurements Research Articles

PM<sub>2.5</sub> 국가기준측정장비 선정을 위한 비교 측정 연구

To establish National Reference Method (NRM) for , operational performance of 5 different commercial gravimetric-based measuring instruments was assessed at Bulkwang monitoring station from January 23, 2014 to February 28, 2014. First, physical properties, design, and functional performance of the instruments were assessed. Evaluation was carried out to determine whether operating method for the instruments and levels of QA/QC activities meet the data quality objectives (DQOs). To verify whether DQOs were satisfied, reproducibility of QA/QC procedures, accuracy, relative sensitivity, limit of detection, margin of error, and coefficient of determination of the instruments were also evaluated. Results of flow rate measurement of 15 candidate instruments indicated that all the instruments met performance criteria with accuracy deviation of 4.0% and reproducibility of 0.6%. Comparison of final mass concentrations showed that the coefficient of determination () values were greater than or equal to 0.9995, and concentration gradient ranged from 0.97 to 1.03. All the instruments satisfied criteria for NRM with the estimated precision of 1.47~2.60%, accuracy of -1.90~3.00%, and absolute accuracy of 1.02~3.12%. This study found that one particular type of measuring instrument was proved to be excellent, with overall evaluation criteria satisfied.

Computer Aided Design of Differential Pressure Flow Meters

New methodology of designing the differential pressure flow meters for fluid energy carriers is developed in order to provide minimum uncertainty of results of flow rate measurement. This methodology is implemented in “Raskhod-RU” CAD system for computer aided design and calculation of differential pressure flow meters. “Raskhod-RU” CAD meets the requirements of new Standards implemented in CIS countries (GOST 8.586.1,2,3,4,5-2005) and provides accomplishment of the following tasks: verification of conditions (constraints) for application of the differential pressure method according to the requirements of new Standards; calculation of parameters of primary device, pipe straight lengths and flow meter in general according to the requirements of new Standards; calculation of uncertainty of results of fluid flow rate and volume measurement.

Effect of low-frequency ultrasound on flow rate measurements using the ultrasonic velocity profile method

This study presents a low-frequency ultrasonic propagation analysis using the finite-element method (FEM). Experimental results of flow rate measurements using the ultrasonic velocity profile (UVP) method are also presented. The ultrasound frequency, pipe diameter, and pipe wall thickness are 0.274 MHz, 590.6 mm, and 9.5 mm, respectively. Six waves are generated per ultrasound pulse. To analyze the entire pipe region, the FEM is combined with the Kirchhoff method. The experiments of flow rate measurements are conducted using the high Reynolds number calibration facility at the National Metrology Institute of Japan. The range of the Reynolds number is from 4.4×106 to 1.7×107. Wide spreading of the ultrasonic beam in the axial direction of the pipe is observed because of multiple reflections in the pipe wall. This wide beam affects the measured velocity profile, particularly in the region near the pipe wall. In addition, the flow rate errors are approximately 10% (deviating by 1.1%) across the investigated range of Reynolds number. This result suggests that the experimental flow rate errors might be used as correction factors of flow rate measurements using the UVP method.

Study of welding of poly(ether-ester) elastomers. Part I. Influence of contents of flexible segments on morphology and mechanical properties

Weldability of poly(ether-ester) (PEE) multiblock elastomers, which belong to the group of the thermoplastic elastomers (TPE), was investigated. Investigated PEE consisted of soft polyoxytetramethylene (FS) blocks and hard poly(butylene terephthalate) (RS) blocks; with the FS:RS ratio variable. Welds were prepared using the wire (rod) welding technique and extrusion welding. Optical and scanning electron microscopy were used to characterize weld morphology and their mechanical properties (elongation, bending, impact strength). Materials for the seams were not dried prior to welding, so hydrolytic degradation took place during welding (250-300 °C), visible particularly in PEEs with higher RS content, as shown by results of flow rate measurements (MFR). The investigations demonstrate that the PEE elastomers containing predominantly the PTMO rich soft phase are well weldable using the applied techniques, even when non-dried material is used for the welds.

Precise measurement of flow rates of vaporized tetraethylgermanium carried by an inert gas

The ‘‘rate-of-rise’’ technique has been applied for the measurement of the flow rate of tetraethylgermanium carried in a stream of argon. A very precise time counter designed and constructed for this purpose is described. A simple model is presented where the flow rate of the vapor is proportional to its partial pressure and to the flow rate of the carrier gas and inversely proportional to the partial pressure of the carrier gas. The assumed applicability of the equation of state of the ideal gas to the discussed system is successfully tested by means of the flow rate dependence on temperature in the range from −19 to 20 °C and its comparison with data computed from the Clausius–Clapeyron equation. Finally thermodynamic properties of tetraethylgermanium namely vaporization enthalpy and saturated vapour pressure at standard temperature are calculated from the results of flow rate measurements.

Étude de la stabilité chimique et mécanique des tubes de pompes technicon lors de l'emploi de solvants organiques très agressifs (amines et éthers)

The resistance of Technicon pump tubing to mechanical usage and chemical attack was studied for aqueous solutions rich in heteropolar organic solvents such as n-butylamine and tetrahydrofuran. The results of flow-rate measurements, over 200 h, with “tygon” (PVC), “solvaflex”, “acidflex” (black/red) and “silicone” tubing indicate that only the last is acceptable for use with the above-mentioned solvents. With the other types of tubing there is rapid solubilization, deformation or rupture of the material. A comparison carried out under identical conditions with distilled water allows the respective importance of chemical attack and mechanical usage to be assessed.