scholarly journals CONTROLLED LIFTING THE BELL OF THE STATE PRIMARY GAS VOLUME AND VOLUME FLOW RATE STANDARD

Author(s):  
Denys Serediuk ◽  
Yuriy Pelikan ◽  
Oleksandr Bas ◽  
Roman Manulyak

The article describes the implemented system of pneumatic lifting of the bell of the state primary standard gas volume and volume flow rate units. The system is composed of unified elements of industrial air preparation. There are elements for air purification in front of the compressor, dehumidifier, refrigerator dryer. With the use of a pneumatic system, the bell can be filled with prepared air with different values of excess pressure. The system is installed as a backup to the current to increase security. Pneumatic lifting of the bell allows you to connect a set of cylinders with pure inert gases or mixtures thereof to determine the impact on the gas meters metrological characteristics.

Author(s):  
Hussein Maghrabie ◽  
Hamouda Mousa

Abstract Recent progress in nanotechnology has lead to a revolution in the automotive cooling system. In the present work, enhancement of car radiator thermal performance was investigated using different nanofluids named SiO2/water, ZnO/water nanofluids as cooling mediums. The present study mainly aims to investigate the impact of (5 wt.%) from SiO2 and ZnO nanoparticles (NPs) dispersed in water based on car radiator heat transfer with spherical and hexagonal morphology, respectively. The experiments were performed in two working conditions of the nanofluids i.e coolant temperature and volume flow rate, moreover the present results were compared with the previous studies. The experimental working conditions were set at coolant inlet temperature (tc,i) ranged from 45 oC to 80 oC and the coolant volume flow rate (V) ranged from 3.5 lit/min to 6.5 lit/min. The experimental results show that the hexagonal ZnO/water nanofluid was superior towards enhancement of car radiator thermal performance comparing to that of SiO2 NPs. Additionally, at 6.5 lit/min and 45 °C, the enhancements of car radiator effectiveness due to using SiO2 and ZnO based water nanofluids and compared with that for the based water were 13.9% and 16%, respectively. The present study used the multiple regression analysis (MRA) and hence empirical correlations are suggested to estimate the overall heat transfer coefficient (U) for all coolants as functions of volume flow rate (V) and the coolant inlet temperature (tc,i) with a maximum STDEV of ± 1.85%.


Author(s):  
Markus Juling ◽  
Jonas Steinbock ◽  
Andreas Weissenbrunner

Precise volume flow rate measurements are very important for various industrial applications. Here, one problem is that the service conditions of a flow meter used in the field differ significantly from the conditions present during calibration. The working conditions such as the pressure, the temperature and the flow profile greatly increase the uncertainty of the flow rate measurement. To address this problem, a new laser-optical flow rate standard (LFS) was developed at the Physikalisch-Technische Bundesanstalt (PTB) that allows flow meters to be calibrated on site, thus greatly reducing the uncertainty of the flow rate measurement. For the LFS, the velocity profile within the pipe is measured with laser Doppler anemometry (LDA). The profile is then integrated to calculate the volume flow rate. Various improvements to LDA have made it possible to measure the flow rate with an uncertainty of less than 0.15 % (k = 2). A comparison of the LFS with the primary standard for thermal energy at PTB, which has an uncertainty of less than 0.04 % (k = 2), revealed a maximum deviation of 0.07 % for Reynolds numbers from 105 to 106, thus verifying the uncertainty of the LFS.


Author(s):  
Igor Petryshyn ◽  
◽  
Olexandr Bas ◽  
◽  

The paper focuses on the need to determine the natural gas heat combustion in order to transition to gas metering in units of energy. The technical organization of gas transportation in the main and distribution pipelines on the territory of Ukraine is shown. A detailed analysis of regulatory and legal support, which regulates the definition and accounting of quantitative and qualitative characteristics of natural gas at gas metering units. The draft Rules for determining the natural gas volume are considered in detail. Specified variants of determining the weighted average value of combustion heat in the case of complex gas supply systems with the use of flow measuring means of gas combustion heat. The necessity and urgency of determining the natural gas heat combustion on measuring systems, which are equipped with duplicate metering units without the installation flow means measuring the heat combustion. Emphasis is placed on the fact that a large number of measuring systems are built on the method of variable pressure drop with the use of standard orifice devices. It is pointed out that this method, according to its physical principle, measures the mass gas flow rate. It is also stipulated that ultrasonic gas meters are often used to complete duplicate metering units. The advantages of ultrasonic meters are given. Attention is drawn to the availability of technical metrological support in Ukraine on the basis calibration prover, which includes two secondary standards gas volume and volume flow rate units. Methods and technical means for determining the natural gas heat combustion are analyzed. The calculation of the gas heat combustion and the Wobbe number based on the density values is shown. It is noted that the value of the gas mass flow rate is related to the value of the gas volume flow rate precisely the value of density. The nonlinear dependence of the gas mass heat combustion for the density, which is associated with a disproportionate change in the percentage of carbon atoms to hydrogen atoms, is shown. The structural scheme of the measuring system with the duplicating metering unit for gas density definition and gas heat combustion calculation is developed. The density calculation and natural gas heat combustion depending on the molar fraction of nitrogen and carbon dioxide in the gas from the minimum to the maximum value is carried out. The linear dependence of the change in the gas heat combustion for the molar fraction of nitrogen is established, on the basis of which the method of controlling the gas heat combustion for measuring systems with a duplicate metering unit is proposed. It is shown that the developed procedure for determining the natural gas heat combustion based on the value of density, which is obtained from the calculation of gas mass flow rate and gas volume flow rate consumption on measuring systems with duplicate metering units exactly satisfies class B and C according to DSTU OIML R 140.


2011 ◽  
Vol 346 ◽  
pp. 593-599 ◽  
Author(s):  
Yun Fei Jia ◽  
De Ren Kong

The measurement uncertainty of vortex flowmeter was examined when the gas flow measured was injected with liquid. This test was performed in a multiphase flow calibration facility. A vortex flowmeter of 50 mm in diameter was installed in a 100 mm test section. The gas volume flow rate was held in 141m3/h and the liquid was injected into the gas flow. The liquid volume fractions used at the gas volume flow rate were 0.0106%, 0.0213%,0.0355%,0.0496%,0.0638%,0.0780% and 0.0922%. The small amount of liquid in the gas as discrete droplet is called discrete liquid phase. Analysis on the vortex shedding frequency obtained from a frequency spectra showed that the strouhal values changed from 0.305 to 0.385 with the discrete liquid phase increasing and the total uncertainty of vortex flowmeter was from 0.869% to 2.196%. The experimental result can supply experimental basis for the measurement error correction of vortex flowmeter worked in gas flow with discrete liquid phase.


Author(s):  
Juanli Zuo ◽  
Wenxi Tian ◽  
Suizheng Qiu ◽  
Guanghui Su

The gas-lift pump has been adopted to enhance the natural circulation capability in the type of lead-bismuth alloy cooled reactors such as ADS and LMFR. The natural circulation ability and the system safety are obviously influenced by the two phase flow characteristics of liquid metal-inert gas. In this study, the numerical research has been performed to evaluate the natural circulation capability of lead-bismuth cooled ADS with gas-lift pump. The drift flow theory, void fraction prediction model and friction pressure drop prediction model have been adopted in this numerical simulation. The effects of the gas flow rate, the bubble diameter and the height of ascension pipe on natural circulation capability of gas-lift pump have been analyzed. The results showed that in bubbly flow pattern, for a fixed value of gas volume flow rate, the natural circulation capability increased with the decrease of the bubble diameter. In the bubbly flow, slug flow, churn flow and annular flow pattern, with the gas volume flow rate increasing, the natural circulation capability initially increased and then declined. As the height of ascension pipe increased, the natural circulation flow rate went up. Besides, the flow parameters influenced the thermal hydraulic characteristics of the reactor core obviously. Therefore, in the practical engineering application, the suitable gas volume flow rate, bubble diameter and the height of ascension pipe are important parameters to the capability of natural circulation in lead bismuth alloy loop of this research. The present work is helpful for revealing the law of enhancing the natural circulation capability by gas-lift pump, and providing theoretical basis of the optimization design of cooling and system safety.


MAPAN ◽  
2020 ◽  
Author(s):  
J. A. Prakosa ◽  
C. M. Su ◽  
W. B. Wang ◽  
B. H. Sirenden ◽  
G. Zaid ◽  
...  

Author(s):  
Joe A. Mascorro ◽  
Gerald S. Kirby

Embedding media based upon an epoxy resin of choice and the acid anhydrides dodecenyl succinic anhydride (DDSA), nadic methyl anhydride (NMA), and catalyzed by the tertiary amine 2,4,6-Tri(dimethylaminomethyl) phenol (DMP-30) are widely used in biological electron microscopy. These media possess a viscosity character that can impair tissue infiltration, particularly if original Epon 812 is utilized as the base resin. Other resins that are considerably less viscous than Epon 812 now are available as replacements. Likewise, nonenyl succinic anhydride (NSA) and dimethylaminoethanol (DMAE) are more fluid than their counterparts DDSA and DMP- 30 commonly used in earlier formulations. This work utilizes novel epoxy and anhydride combinations in order to produce embedding media with desirable flow rate and viscosity parameters that, in turn, would allow the medium to optimally infiltrate tissues. Specifically, embeding media based on EmBed 812 or LX 112 with NSA (in place of DDSA) and DMAE (replacing DMP-30), with NMA remaining constant, are formulated and offered as alternatives for routine biological work.Individual epoxy resins (Table I) or complete embedding media (Tables II-III) were tested for flow rate and viscosity. The novel media were further examined for their ability to infilftrate tissues, polymerize, sectioning and staining character, as well as strength and stability to the electron beam and column vacuum. For physical comparisons, a volume (9 ml) of either resin or media was aspirated into a capillary viscocimeter oriented vertically. The material was then allowed to flow out freely under the influence of gravity and the flow time necessary for the volume to exit was recored (Col B,C; Tables). In addition, the volume flow rate (ml flowing/second; Col D, Tables) was measured. Viscosity (n) could then be determined by using the Hagen-Poiseville relation for laminar flow, n = c.p/Q, where c = a geometric constant from an instrument calibration with water, p = mass density, and Q = volume flow rate. Mass weight and density of the materials were determined as well (Col F,G; Tables). Infiltration schedules utilized were short (1/2 hr 1:1, 3 hrs full resin), intermediate (1/2 hr 1:1, 6 hrs full resin) , or long (1/2 hr 1:1, 6 hrs full resin) in total time. Polymerization schedules ranging from 15 hrs (overnight) through 24, 36, or 48 hrs were tested. Sections demonstrating gold interference colors were collected on unsupported 200- 300 mesh grids and stained sequentially with uranyl acetate and lead citrate.


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