Gas Volume Flow Rate Research Articles

Study of metrological characteristics of household gas meters when measuring the volume flow rate of gas-hydrogen mixtures

The paper presents the results of studies of the influence of pure gaseous hydrogen and gas-hydrogen mixtures and the performance and metrological characteristics of membrane-type gas meters used in the household sector. For the study, membrane-type meters of leading domestic and European manufacturers were pre-selected. A series of static and dynamic tests were conducted for the meters. The static tests involved checking the air-tightness of the meters under the influence of gaseous mixtures. The dynamic tests involved measurements on a simulated test site with a work medium of pure hydrogen as well as hydrogen-methane mixtures. The proportions of the mixtures used were: 80% of methane and 20% of hydrogen, and 90% of methane and 10% of hydrogen respectively. A structural diagram of the measuring system was developed. The measurements were performed by comparing the volume of the gas that passed through the experimental meter with the volume measured by the reference meter. The measuring system was equipped with a means for measuring the pressure and temperature of the measuring medium to bring the results of the experiments to standard conditions. As a reference means in the assembled measuring system, a drum-type gas meter with a calibration characteristic pre-determined under laboratory conditions with a work air medium was used. After the experimental studies with the work hydrogen medium and hydrogen gas mixtures under the conditions of the test site, the metrological characteristics were re-determined under laboratory conditions for the reference meter. To conduct the experiments with the maximum possible accuracy and to exclude the influence of additional errors on the measurement result, a specialized software was developed to automate the measurements of the volume of the gas passing through the reference meter, measuring the pressure and temperature of the work medium and fixing the required value of the gas volume flow rate. The results of the experiments for several meters are presented in the form of tabular values and graphs. General conclusions were made regarding the influence of hydrogen and gas-hydrogen mixtures on the change in metrological characteristics of household gas meters.

Dehydration by Pervaporation of an Organic Solution for the Direct Synthesis of Diethyl Carbonate

Pervaporation has been a central subject in the research community within the scope of the further development of energy- and cost-efficient alternatives to conventional liquid–liquid separation technologies. The potential eligibility of four commercial membranes (ZEBREX ZX0, PERVAPTM 4155-80, PERVAPTM 4100, PERVAPTM 4101) for use in an integrated dehydration application of a diethyl carbonate/water/ethanol mixture by pervaporation was assessed experimentally. The impact of feed concentration, operating temperature, pressure, and sweep gas flow rate on membrane separation performance, including permeation flux, permeate quality, selectivity, and permeance, was thoroughly investigated. Applying the ZX0 membrane delivered the best qualities of all tested membranes of the permeate stream, with a water concentration of mostly >98%. In comparing the water flux, the ZX0 membrane remained reasonably competitive with the polymer membranes. Furthermore, the sweep gas volume flow rate and the operating temperature were identified as influencing the flux significantly but not the product composition. At the same time, the feed concentration of water also influenced the water purity within the permeate. The experiments were monitored with a partial least squares model, allowing a quick assessment of obtained samples while delivering accurate results.

Numerical study of temperature distribution in a solar receiver with a focus on water heating in an internal helical tube

Solar energy is one of the clean energies that many researchers have focused on. This study used the Monte Carlo Ray Tracing (MCRT) method in MATLAB coding to calculate the water temperature inside a solar receiver containing a spiral coil through which water passes. To guess the amount of solar radiation that would hit the receiver and figure out the temperature of the water coming out, the Monte Carlo method was used. The three cases were: a change in the receiver's exposure time to solar radiation (t = 2, 4, 6, 8, 10 h); a change in the gas flow rate (Qg = 5, 10, 15, and 20 L/min); and a change in the water flow rate (from 2 to 20 with an increase of 2 L/min in each case. The study found that the gas volume flow rate (Qg) slightly affected the thermal distribution at Qg = 5 L/min, Tg = 358 C, and at Qg = 20 L/min, Tg = 352 C, while the water volume flow rate (Qw) and time directly affected the water temperature. The study showed that the thermal distribution was stable at 8 and 10 h. At 8 h, the water reached a maximum temperature of 153 °C at Qg = 5 and Qw = 2. When Qg = 5 L/min and Qw = 2 L/min, the receiver wall temperature reached 322 °C, the receiver backplate temperature (Tbp) reached 498 °C, and the gas temperature (Tg) reached 354 °C. At QG and Qw = 20, the water temperature dropped to 46 °C. This showed that the volume flow rate significantly affected the temperature.

Influencing the powder particle transport in high-speed laser melt injection

Using high-speed laser melt injection (HSLMI), it is possible to generate wear-resistant metal matrix composite (MMC) surfaces on tools with great productivity. Since high laser intensities are required for reaching high process speeds, strong interactions can occur between powder particles and the laser beam. In order to reduce the interaction time and gain a better understanding of the role of particle transport in the HSLMI process, trajectories of spherical fused tungsten carbide (SFTC) particles were analyzed using high-speed imaging. The trajectories were divided into a path outside the laser beam and a path inside the laser beam. The identified interaction mechanisms were particle deformations, the formation of agglomerates, and particle disintegration. The volume flow rate of the feeding gas was found to have a decisive influence on the travel time of the particles, whereas the powder feed rate and the working distance of the powder nozzle only had a minor influence. Consequently, an increased volume flow rate led to a significant reduction of interactions between SFTC particles and the laser beam.

CFD investigation of chalcopyrite flotation prediction coupled with flotation kinetic model

CFD (computational fluid dynamics) simulation plays an important role in flotation prediction research and application. The flotation process of chalcopyrite in a three-dimensional mineralized tube was simulated coupled with flotation kinetic model. Regarding kinetic prediction model in the flotation process is explored at gas flow rate of 0.06 m3/h, slurry flow rate of 0.4 and 0.5 m3/h, including collision probability model, attachment probability model, detachment probability model and bubble slip velocity model. Flotation experiments of chalcopyrite is performed, and the simulation of flotation process is realized by adding UDF (user-defined function). Furthermore, the flotation rate constant is taken to verify the validity of the model. The prediction error of flotation rate constant is 19 % and 17 % between flotation experiments and simulations at slurry flow rate of 0.4 and 0.5 m3/h, respectively. According to the combinations of flotation kinetic model, it’s found that the prediction results of Yoon-Luttrell collision probability model, Yoon-Luttrell attachment probability model, Schulze detachment probability model and Kostoglou bubble slip velocity model are superior to other combinations. the prediction error of flotation rate constant is 8 % at the slurry flow rate of 0.4 m3/h.

Fast pyrolysis of agricultural biomass in drop tube reactor for bio-oil production: Numerical calculations

Fast biomass pyrolysis is an effective method for bio-oil production and can be performed in fluidised beds, augers, and drop-tube reactors. In this study, the fast pyrolysis of agricultural biomass (oat and corn straw) in a drop-tube reactor was investigated by applying multiparameter analysis involving numerical calculations. The main motivation for this analysis was to determine the operating parameters for fast pyrolysis under which the highest bio-oil production was achieved. In this study, the following operating parameters were involved: pyrolysis temperature (500 – 700 °C), volume flow rate of the carrier gas (3 – 5 l/min), mass flow rate of the feedstock (10 – 30 g/h), and diameter of the particle (250 – 750 µm). The analysis was performed using numerical methods with the Euler-Lagrange multiphase theory in a 2D axisymmetric model. According to the numerical results, selection of a particle size of 500 µm, pyrolysis temperature of 500 °C, and nitrogen flow rate of 3 l/min allows obtaining 51.16% and 52.09% of bio-oil for oat straw and corn straw pyrolysis, respectively. The biomass mass load did not influence the final product yield. The numerical results were successfully confirmed by experimental investigations where experiments supplied 53.2% and 51.3% of bio-oil to oat straw and corn straw, respectively.

MASTER METER PROVER FOR VERIFYING GAS METERS IN THE GAS VOLUME FLOW RANGE UP TO 6500 M3/H

In the article, the need to create a master meter prover for verifying gas meters in the gas volume flow range up to 6500 m3/h in SE Ivano-Frankivskstandardmetrology is presented. An analysis of the existing prover’s types was carried out, indicating the advantages and disadvantages. Reasonable selection master meters of the rotary, turbine and drum type as part of the prover. Features the master meters volume flow ranges, which overlap each other, are determined. The stages of modeling the piping of the reference prover are given. The stages the calibration methodology the reference prover are described. The initial stage involves the calibration of pressure and temperature sensors, which are mounted as part of the prover to exclude the influence of the installation. Calibration the master meters is carried out with the help of transfer standards, which are calibrated on national standards gas volume and volume flow rate. The components of uncertainty that affect the calculation of expanded uncertainty are described in detail. The features of the developed prover software, which contains the requirements of new verification methods for gas meters of various types, are given.

Analysis of the outcome of blow-out operation in EAST manifold

Prior to equipment maintenance and “baking” operation, the Experimental Advanced Superconducting Tokamak (EAST) carries out a “blow-out” operation. Utilizing a manifold structure, pressurized nitrogen gas is driven into the Plasma Facing Components (PFCs)' cooling channels to eject residual cooling water. The “outcome” of the blow-out operation, the final steady-distribution of the gas-liquid two-phase in the manifold, significantly influences the efficiency, the time and energy cost of the subsequent drying process and indirectly shapes the quality of the vacuum environment required for plasma operation. In this context, this paper presents a theoretical analysis and simulation of the outcome of blow-out operation of EAST manifold. The analysis discusses three kinds of steady distribution state within a manifold branch: “Stagnant", “Two-phase flow", and “Near-dry flow". It is observed that stable “Two-phase flow” cannot be maintained when multiple branches flow concurrently due to the unstability of parallel flows. Thus, in such scenarios, the branch primarily exhibits only “Stagnant” and “Near-Dry” states. Furthermore, the total gas flow rate plays a significant role in determining the number of “Near-Dry” branches. Simulation provides specific quantities prediction of “Near-Dry” branches under varying gas volume flow rates. Finally, the theoretical analysis and simulation results is validated through experimental data. This study offers valuable insights for optimizing future blow-out operations of the EAST manifold.

Design optimization of a rotating packed bed based on dry hydraulic performance

The current study focuses on enhancing the fidelity of the hydraulic performance of Rotating Packed Beds (RPB) by modifying the conventional geometrical construction of the inner cavity, outlet pipe, and its packing. RPB technology has been playing an increasing role in intensifying different petrochemical processes, such as CO2 capture, due to the potential of a several-order-of-magnitude mass transfer enhancement induced by the HiGee field. In this context, four novel geometries of the RPB are proposed and analyzed using a validated CFD model that utilizes the porous media approach to model the pressure losses in the RPB packing. The impact of liquid distributor was also investigated and compared to the original design. Results of the modified geometries conclude that optimizing the flow pattern at the exit of the packing by modifying the inner cavity's shape reduces the total pressure drops by up to 22%. At the same time, it is found that a further decrease of 13% in the pressure drop can be achieved by attaching a nozzle at the entry of the outlet pipe. On the other hand, the modified packing that imposes a constant radial flow velocity increases the packing's pressure drop by 10%. Furthermore, the data analysis show that a lower pressure drop within the inner cavity could be achieved, in principle, by regulating the exit packing velocity or raising the free vortex pressure. Finally, it is noted that the gross pressure drop reduction, which is be obtained from combining the two former modifications, can reach up to 33% at the high gas volume flow rates. This reduction accounts for 60% of the inner cavity pressure drop, which can help avoid costly and complicated engineering designs.

Experiments on Slug Flow Dynamics in Helically Coiled Tubes

Slug flow characteristics in helically coiled tubes were investigated in experiments. Pressure loss, slug velocity, and slug passing frequency were measured using pressure transducers and backlight imaging of dyed water under illumination. For a 20-mm-diameter tube, parametric dependencies on gas and liquid volume flow rates for total superficial velocities of up to 6 m/s with three different radii of curvature (R = 0.270 m, R = 0.375 m, and R = infinity/straight tube) were explored. The main experimental results obtained are (1) the bubbly flow regime shrinks because of centrifugal acceleration from the coiled geometry, (2) the liquid slug length remains unchanged regardless of changes in gas and liquid flow rates, and (3) the pipe friction factor decreases with slug passing frequency.

A Novel Method for Wet Gas Flow Measurements Based on an Over-Reading Principle

A novel method to measure the flow rate in a wet gas is presented. Due to the presence of liquid, there is a deviation in the measurement of the gas volume flow rate obtained with standard vortex flow-meters. The proposed method is based on a correction factor determined through the application of an over-reading approach to a bluff body in mist flow. The correction factor is obtained from the slip velocity ratio, i.e., the ratio of droplet velocity to gas velocity, based on the analysis of the fluid velocity distribution in the pipeline section. It also takes into account relevant theoretical arguments. It is shown that the predicted results fit the experimental results well.

The Investigation of Gas Distribution Asymmetry Effect on Coriolis Flowmeter Accuracy at Multiphase Metering.

Multiphase flows are encountered in various industries, and the Coriolis flowmeter (CFM) is considered a high potential flowmeter for the metering of these flows. However, the decoupling effect and asymmetrical gas distribution in a CFM might decrease the accuracy of its multiphase flow metering The asymmetry of gas distribution in a CFM and its influence on the metering accuracy have only been qualitatively investigated in a few studies. The present paper quantitatively describes the gas distribution asymmetry in several CFMs under different flow conditions by numerical simulation. The simulation methodology is developed and validated by a results comparison with a conducted experiment and published data for bubbly, stratified and transitional flow regimes. U-shaped and triangle-shaped CFMs of different diameters are investigated at different gas volume fractions and flow rates. It is shown that the increase in the gas volume fraction and the reduction in the mixture flow rate lead to the increase in the gas distribution asymmetry. The strong correlation between the gas distribution asymmetry and the experimentally observed CFM error is demonstrated. The correction of the CFM error is proposed based on this correlation allowing the metering error to be decreased from 34% to 10% for the investigated conditions.

Water Model Experiments on the Influence of Phase Distribution in the Submerged Entry Nozzle Considering Varying Operating Conditions

Continuous casting of steel argon injection into the submerged entry nozzle (SEN) via the stopper is common practice. Nonetheless, the resulting phase distribution in the SEN is still under discussion. The main available casting parameters at the steel plant to determine the flow situation in the SEN are usually the stopper rod position, the argon feeding pressure, the argon flow rate, and the casting speed. To show the potential influence of the phase distribution on the stopper characteristic and on the argon feeding pressure, experiments using a 1:3 scale water model are presented. For the experiment, the water flow rate is scaled using Froude similarity, while the air flow rate is chosen to keep the ratio between the liquid and gas volume flow rate constant. The casting parameters and the pressure at three distinct levels of the SEN are measured. To relate this measurement data to the corresponding phase distribution, two cameras are used to document the phase distribution in the SEN. The images show four major phase distribution patterns. These patterns can be linked to significant changes in the measured pressure levels and the behavior of the stopper.

Metrological research of a reference installation based on a high-pressure vessel

The urgency of development and metrological research of reference installations based on high-pressure vessels, which meet the requirements of the implementation of traceability of instruments for measuring gas volume and gas volume flow rate, is considered. The operation algorithm of the specified reference installations when transferring the unit of gas volume to the gas meters under consideration is studied. Based on the algorithm and features of the operation of PVTt-type standards, a list of the analysed uncertainties of type A is formulated when estimating the volume of the calibrated high-pressure vessel; when measuring the absolute pressure and absolute temperature of gas due to the influence of instability of pressure and temperature on the gas meter under consideration due to the presence of a temperature gradient in the vessel. Uncertainties of type B, which are determined by metrological characteristics of measuring instruments, as well as the uncertainty of parameters evaluated by means of calculation, in particular the compressibility factor of the working environment, the influence of water vapour on the working environment and the influence of the discreteness of the device for collecting information about measurements from the gas meter are considered.
 Formulas to quantify the combined uncertainty of measuring the volume of the calibrated vessel, the absolute pressure and absolute temperature as well as to calculate the air compressibility factor for the operating conditions of the installation are given. These parameters are the absolute pressure and absolute temperature of the gas and the compressibility factor of the working environment in the vessel at the beginning and at the end of the reproduction of the reference volume as well at the inlet of the gas meter. The expressions for calculating the combined and expanded uncertainties of PVTt-type standards are given.

Numerical Investigations for the Two-Phase Flow Structures and Chemical Reactions within a Tray Flue Gas Desulfurization Tower by Porous Media Model

The computational cost of the full-scale flue gas desulfurization (FGD) tower with perforated sieve trays is too high, considering the enormous scale ratio between the perforated hole at the sieve tray and the relevant size of the full-scale tower. As a result, the porous media model is used to replace the complex perforated structure at the sieve tray in this study, which has been validated for the measured data for both the small- and full-scale FGD tower. Under a lower inlet gas volume flow rate, the simulation result of the four-tray tower indicates that the uprising gas flow of high SO2 mass fraction can move along the wall of the tower. This region lacks two-phase mixing and, hence, its desulfurization efficiency is similar to that of empty and one-tray towers under the same flow conditions. However, when the gas volume flow rate increases, the liquid column becomes larger because of the stronger inertial of the uprising gas flow. In this situation, the implementation of the sieve tray suppresses the deflection of liquid flow and provides a better mixing within sieve trays, leading to a noticeable increase in desulfurization efficiency. This study provides insightful information for the design guideline for the relevant industries.

Falling film co-current flow cyclone demister for separating high-boiling droplets: Gas-liquid flow pattern and performance

In many processes, the product gas stream contains liquid droplets that easily condense or solidify, which can deteriorate demister performance and even block equipment during gas–liquid separation. We proposed a falling film co-current flow cyclone demister (F2CFCD) to solve the above problems. The novel idea is that an additional stream of solvent fluid is added to the gas stream containing the droplets. After injecting the demister, the solvent fluid forms a film on the wall of F2CFCD. When the droplets are separated to the wall surface by centrifugal force, they are dissolved by the liquid film, thereby avoiding crust formation. In this work, the gas–liquid flow characteristics and the performance of F2CFCD are investigated numerically and experimentally. A hot-wire anemometer (HWA) is used to measure the gas velocity, and a conductivity method is used to measure the liquid film thickness. A coupled numerical model of the RSM-DPM and Eulerian wall film (EWF) model is applied to discuss the effect of the gas–liquid flow rate on the flow field in the demister. The liquid volume flow rates ranges from 0.5–10.5 m3/h, and the gas volume flow rates range from 640–894 m3/h. The gas flow pattern and the liquid film flow regimes are explored in the F2CFCD. A film thickness model is established to evaluate the average film thickness in the waterfall regime. Experimental observations illustrate that F2CFCD has a high separation efficiency for droplets under all conditions.

Nanoporous polypropylene membrane contactors for CO2 and H2S capture using alkali absorbents

The paper reports a comprehensive review of the performance of nanoporous gas-liquid polypropylene membrane contactor with NaOH absorbents for removal of H2S and CO2 components from the gas streams. The experiments at different operation conditions, including variation of acid gas content in a feed stream, alkali concentration in absorbent, gas and liquid absorbent volume flow rates, absolute and gas-liquid differential pressures are discussed as a function of the absorbent saturation levels. In-liquid diffusion of components and gas/membrane contact times were determined as main governing factors limiting contactor efficiency. Mass transfer rates of acid gas removal on the membrane contactor over 3 × 10−3 mol/(m2 × s) for CO2 and 7.5 × 10−3 mol/(m2 × s) for H2S were attained. Ultimate processed gas quality with H2S content below 5 ppm and CO2 content below 0.01% was achieved at the contactor performance over 7 m3/(m2 × h) and initial acidic gas content of 2%, while achieving a membrane packing density in the contactor over 3000 m2/m3. The paper also provides an experimentally-proven theoretical model for calculating removal efficiency and residual acid gas partial pressures depending on the membrane parameters and operation conditions. It is shown, the mass transfer coefficient and removal efficiency differ significantly for H2S and CO2 due to the difference in dissolution mechanism involving kinetically limited deprotonation reaction of solvated water in case of CO2(aq) while engaging direct deprotonation of H2S. This allows to attain residual partial pressure of H2S in retentate stream equal to the equilibrium pressure above the absorbent solution, while CO2 residual pressure exceeds an equilibrium value few orders of magnitude. The effect has been successfully utilized for the selective removal of H2S from both CO2 and H2S-containing mixtures with H2S/CO2 selectivity exceeding 1500.

Measurement Standards of Ukraine for Gas Volume Flow Rate at Pressures of 1 MPa to 5 MPa

The characteristics of the primary measurement standards of the volume gas flow rate at high pressure developed in various countries are considered. A hierarchical scheme for gas flow measuring instruments and a corresponding metrological traceability chain are presented. Described is a PVTt method, on which the primary standards of gas flow rate used in the USA, France, Japan, and Taiwan are based. The need to create in Ukraine primary measurement standards of gas flow rate at high pressure covering different parts of the total flow rate interval from 0,3 m3/h to 1800 m3/h at a pressure of 1 MPa to 5 MPa is substantiated. Metrological traceability of gas flow measurements is realized through a sequence of critical flow Venturi nozzles, which play a role of the reference flow rate material measures. The standards might be used to calibrate the primary reference Venturi nozzles of the most common 0,1 mm to 8 mm diameters. The characteristics and parameters of the standards are determined. By their metrological and technical characteristics, the standards will correspond to the state-of-the-art level. According to the programme of developing the measurement-standard facilities in Ukraine, in 2019 the primary standard PVTt-65 was created and work had started on the development of the primary standard PVTt-1800 and the working standard PE-5400. A detailed study of the metrological characteristics of the measurement standards will be the topic of further work.

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

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.

An in-situ calorimeter for coal powder: A numerical investigation

Timely monitoring of the calorific value of coal is beneficial to combustion regulation during the operation of coal-fired power plants. An in-situ measurement system applied to power plants was proposed. The related model was described in detail and validated through bomb calorimetry. The influences of multiple model parameters with different thermometer and flowmeter accuracy on measurement time and uncertainty have been analyzed. Measurement properties of the bomb calorimeter and this improved calorimeter were compared at different conditions. The results reveal the increases in the gas volume flow rate and the water mass flow rate have a positive effect on measurement time while coal mass and the mass ratio of water in two cylinders show a negative effect. Relative standard uncertainties are reduced to some extent with all of these factors. It is evidenced the proposed calorimeter has the potential for fuel calorific value monitor for power plant operation optimization.