Flowmeter Tube Research Articles

Quantifying ventilation by X-ray velocimetry in healthy adults

RationaleX-ray velocimetry (XV) has been utilized in preclinical models to assess lung motion and regional ventilation, though no studies have compared XV-derived physiologic parameters to measures derived through conventional means.ObjectivesTo assess agreement between XV-analysis of fluoroscopic lung images and pitot tube flowmeter measures of ventilation.MethodsXV- and pitot tube-derived ventilatory parameters were compared during tidal breathing and with bilevel-assisted breathing. Levels of agreement were assessed using the Bland-Altman analysis. Mixed models were used to characterize the association between XV- and pitot tube-derived values and optimize XV-derived values for higher ventilatory volumes.Measurements and main resultsTwenty-four healthy volunteers were assessed during tidal breathing and 11 were reassessed with increased minute ventilation with bilevel-assisted breathing. No clinically significant differences were observed between the two methods for respiratory rate (average Δ: 0.58; 95% limits of agreement: -1.55, 2.71) or duty cycle (average Δ: 0.02; 95% limits of agreement: 0.01, 0.03). Tidal volumes and flow rates measured using XV were lower than those measured using the pitot tube flowmeter, particularly at the higher volume ranges with bilevel-assisted breathing. Under these conditions, a mixed-model based adjustment was applied to the XV-derived values of tidal volume and flow rate to obtain closer agreement with the pitot tube-derived values.ConclusionRadiographically obtained measures of ventilation with XV demonstrate a high degree of correlation with parameters of ventilation. If the accuracy of XV were also confirmed for assessing the regional distribution of ventilation, it would provide information that goes beyond the scope of conventional pulmonary function tests or static radiographic assessments.

Optimal Design Parameters of Thermal Flowmeter for Fuel Flow Measurement.

The article analyses the influence, relationship and value of the design parameters of the thermal flowmeter on its radial and axial heat fluxes in the tube. The purpose of the analyses is to check the change in the error of fuel flow measurement by the thermal flowmeter directly on the vehicle when using heating elements of different diameters. The influence of the radial heat flux of the flowmeter tube on the accuracy of fuel flow measurement is substantiated. Recommendations on the choice of design parameters of a thermal flowmeter at the stage of its design, development or use are developed under the condition of reducing the influence of the radial heat flow on the axial one, which will reduce the total error in the measurement of fuel flow rate.

Fluid-Solid Interaction Simulation Methodology for Coriolis Flowmeter Operation Analysis.

Numerical simulation is a widely used tool for Coriolis flowmeter (CFM) operation analysis. However, there is a lack of experimentally validated methodologies for the CFM simulation. Moreover, there is no consensus on suitable turbulence models and configuration simplifications. The present study intends to address these questions in a framework of a fluid-solid interaction simulation methodology by coupling the finite volume method and finite element method for fluid and solid domains, respectively. The Reynolds stresses (RSM) and eddy viscosity-based turbulence models are explored and compared for CFM simulations. The effects of different configuration simplifications are investigated. It is demonstrated that the RSM model is favorable for the CFM operation simulations. It is also shown that the configuration simplifications should not include the braces neglect or the equivalent flowmeter tube length assumption. The simulation results are validated by earlier experimental data, showing a less than 5% discrepancy. The proposed methodology will increase the confidence in CFM operation simulations and consequently provide the foundation for further studies of flowmeter usage in various fields.

Вплив деяких параметрів конструкції теплового витратоміра палива на передачу тепла в ньому

The article analyzes the influence, relationship and value of design parameters of the heat flow meter on its radial and axial heat fluxes in the tube (tube diameter, heater diameter and their ratio, thermal conductivity of the tube material, etc.). It is shown that at the stage of choosing the design parameters of the flowmeter it is necessary to take into account the influence of its radial heat flux on the axial one. The influence of radial heat flux in the flowmeter tube on the error of fuel loss measurement is substantiated. Analytical dependences which allow to define an axial heat stream are resulted, their analysis concerning influence of flowmeter tube constructive parameters on heat transfer is carried out. Measures are planned and recommendations are developed for the choice of design flowmeter parameters, development or use, provided that the influence of radial heat flow on the axial is reduced, which will reduce the total error of fuel consumption measurement. Regarding the choice of design parameters of heat meters while reducing the error of measuring fuel consumption, it is shown that the maximum possible decrease in the diameter of the heater and increase the diameter of the flow tube reduce the impact of radial heat flow on the axial and thus reduce the total fuel consumption error. Numerical ratios of tube diameter to flowmeter heater diameter for different thermal conductivities of tube materials are given under the condition of minimal influence on fuel consumption measurement error. For tube materials with a thermal conductivity 0.16… 0.25 W / (m ∙ K) (ebonite, fluoroplastic F-5, etc.) the tube diameters ratio and the heater should be within 1.51… 1.62, and for materials with more high thermal conductivity (thermal conductivity greater than 14.9 W / (m ∙ K)), this ratio should be equal to 1.99.

Development and demonstration of CO2 flow numerical calibration system – part II

This project takes the flue at the tail of Fujian Kemen Power Generation Company as the research object. Calibration factor, precise flow value, etc. Through the above analysis, it is concluded that the ultrasonic flowmeter has high requirements on the location selection, and the measurement result is closer to the true value. The matrix type flowmeter is easy to arrange, and the location selection sensitivity is low; the single point pitot tube flowmeter has poor accuracy and is not recommended.

Experimental and numerical study on thermodynamic performance in a designate pilot-ignition structure: Step

Reliable ignition and stable flame spreading were extremely important especially for the increasing expansion of flight envelope. A new pilot-ignition structure- step- was put forward with low resistance and developed to meet more critical challenges. To optimize structure parameters, thermodynamic performance with various step heights (30 mm, 40 mm, 50 mm, and 60 mm) was investigated in premixed combustion, such as ignition and blow-off loop measured by intelligent metal tube flowmeter, and flame development recorded by high-speed camera. Additionally, numerical simulation of flow field was performed to analyse the influence of flow pattern on thermodynamic characteristics. It was found that flow pattern occurred transition with the increase of step height, namely, couple-vortex recirculation in 30 mm-height step structure and single-vortex recirculation in the other three. Additionally, the four kinds of steps realised successful ignition and stability loop. Specially, ignition and blow-off performance of 30 mm-height step structure with particular couple-vortex recirculation was sensitive to temperature, and improved with the growing temperature; also its ignition limits were increasing with the growing velocity, especially up to 200 m/s, ignition limits were almost lower than the others. Once ignited, flame development rate had a convex-function relation to temperature and optimized temperature existed at an extreme point (at 800 K), it decreased progressively with growing velocity. Moreover, flame spreading height up to core flow increased first and then decreased with growing temperature, and it was monotone decreasing with the growing inlet velocity. The step structure conducted in this work was validated for its reliable ignition and broad stability loop. Low-resistance pilot ignition design was developed and employed for turbojet/ramjet.

Simulation and Optimization of Throttle Flowmeter with Inner-Outer Tube Element

Abstract In order to solve the dilemma between the smaller pressure loss and the larger flow measurement signal in traditional throttle flowmeters, a throttle structure with the inner-outer tube was designed and analyzed. The mathematical relationship model deduced from hydrodynamics showed there were three major parameters to determine the designed throttle structure. Furthermore, the optimal results were achieved by combining orthogonal test design and computational fluid dynamics by taking the ratio of differential pressure of inner-outer tube divided by that of anterior-posterior tube as the optimization goal. Finally, the simulation results with the best level parameters showed that the differential pressure of the anterior-posterior throttle could remain not only the smaller value among other parameters with the same structure of inner-outer tube. On the other hand, it was about one order magnitude less than differential pressure of V-cone flowmeter in the similar installation conditions with the flow velocity varying from 0.5 to 3.0 m/s. The designed inner-outer tube flowmeter can not only save manufacture costs, but also avoid the large sensitivity of pressure sensors, which may lead to a broader application in chemical and petrochemical enterprises.

MEMS-based micro-Coriolis technology for high precision density measurement

Abstract Endress+Hauser has a long history of developing and producing flowmeters of various measurement technologies for the scope of process and product control in a variety of applications and industries. One of the most important flow measurement technologies in the last decades was the vibrating tube flowmeters based on the Coriolis measuring principle. An advantage of Coriolis flowmeters is the fact that they measure direct mass flow rate. Furthermore, by using the resonating tube frequency information, density and viscosity of a fluid can be deduced. Coriolis flowmeters exist in a lot of different shapes and styles, typically having metal flow tubes e. g. from stainless steel, titanium, zirconium or tantalum. The nominal flow rates range from about 1 g/h to 4000 t/h corresponding to line sizes from 0.2 mm up to 350 mm. In recent years different groups have worked on the adaptation and implementation of the Coriolis measuring principle in a MEMS (Micro Electro Mechanical System) sensor by etching a micro tube structure from a silicon wafer. Such micro machined silicon based Coriolis sensor chips open a new field of applications for the Coriolis measuring principle. Here we present the work of Endress+Hauser on the field of MEMS based Micro-Coriolis Sensors and explore potential applications of this new technology, e. g. for very accurate liquid and gas density measurements and concentration determination.

Series Supply of Cryogenic Venturi Flowmeters for the ITER Project

In the framework of the ITER project, the CEA-SBT has been contracted to supply 277 venturi tube flowmeters to measure the distribution of helium in the superconducting magnets of the ITER tokamak. Six sizes of venturi tube have been designed so as to span a measurable helium flowrate range from 0.1 g/s to 400g/s. They operate, in nominal conditions, either at 4K or at 300K, and in a nuclear and magnetic environment. Due to the cryogenic conditions and the large number of venturi tubes to be supplied, an individual calibration of each venturi tube would be too expensive and time consuming. Studies have been performed to produce a design which will offer high repeatability in manufacture, reduce the geometrical uncertainties and improve the final helium flowrate measurement accuracy. On the instrumentation side, technologies for differential and absolute pressure transducers able to operate in applied magnetic fields need to be identified and validated. The complete helium mass flow measurement chain will be qualified in four test benches: - A helium loop at room temperature to insure the qualification of a statistically relevant number of venturi tubes operating at 300K.- A supercritical helium loop for the qualification of venturi tubes operating at cryogenic temperature (a modification to the HELIOS test bench). - A dedicated vacuum vessel to check the helium leak tightness of all the venturi tubes. - A magnetic test bench to qualify different technologies of pressure transducer in applied magnetic fields up to 100mT.

Potential use of capillary tube thermal mass flow meters to measure residential natural gas consumption

Accurate natural gas measurement is an important issue especially in domestic usage level in which the lack of accurate measurement is well sensed. On the other hand, thermal mass flow meters are widely used in industries such as semiconductor manufacturing and chemical processes. Capillary tube thermal mass flow meter is one of the most common types of thermal mass flow meters which are mostly used for low mass flow rates. In this work, the use of capillary tube mass flow meters for measuring residential natural gas consumption, where the flow rate is extremely low, was proposed. A capillary tube flow meter was simulated, two-dimensional steady state heat transfer in its sensor tube was numerically analyzed and the sensitivity of this type of flow meter to Methane, as natural gas is mainly constituted by Methane, was investigated. In order to validate the simulation approach and conditions taken in this study, the simulation was also accomplished for Nitrogen, for which experimental data was available in the literature, leading to satisfactory results. Considering all the possible effective parameters, the uncertainty of the flow meter was also calculated to be 1.56%. Finally, the simulation was accomplished for a sample natural gas composition with 94.38% methane, resulting to an uncertainty equal to 1.83%.

Numerical analysis of installation effects in Coriolis flowmeters: Single and twin tube configurations

A fully coupled, partitioned, numerical model that accounts for fluid–structure interaction is applied for a study of the installation effects of Coriolis flowmeters. The modeled configurations include a single straight-tube full-bore flowmeter and two different twin tube flowmeters with straight and U-shaped measuring tubes. Three different flow disturbance elements positioned upstream of the flowmeter are considered in the study, as well as two different types of flow splitters in the case of the twin tube configurations. The installation effects are estimated by comparing the mass-flow sensitivities under the disturbed and fully developed flow conditions at the inlet of the flowmeter. For the modeled twin tube flowmeters they are found to be of the order of one-tenth of a per cent. These relatively small values of the installation effects are related to the presence of flow splitters and to the averaging of the motion of both measuring tubes in the twin tube configurations. Similarly, averaging the response from two sensor pairs instead of only a single sensor pair reduces the circumferential variations and the peak values of the installation effects for asymmetric flows in the single straight-tube flowmeter.

Heat transfer in thermoanemometric biofuels flowmeter

The article introduces the equations which reflect variations of the thermal conductivity coefficient of a mixture of petroleum-based fuels, depending on the volume percent concentration of ethanol, and variations of the thermal conductivity coefficient of mixtures of fuels with diesel fuel as a basis, depending on the volume percent concentration of the vegetable oil.It is shown that the fuel temperature at the level of its consumption ranging from 0 to 25 l/h at a distance from 1 to 6 cm from the heater of a flowmeter can be represented by a straight line approximation.Analyzed are radial and axial heat flows in the tube of a termoanemometric flowmeter taking into consideration the influence of the thermal conductivity of biological components of the fuel, their concentration in the fuel mixture. The proposed equations allow us to determine the temperature of the fuel stream and the consumption rate of a car.It is proven the numerical value of the termoanemometric flowmeter tube structural coefficient, which under the condition of reducing the measurement error of fuel consumption must be equal to 15,5.It is proven that the thermal conductivity of the material of a flowmeter tube has little effect on heat flux.

Research of Intelligent Integrated Averaging Pitot Tube Flowmeter

Averaging Pitot tube flowmeter often uses a separated structure which is not convenient. The research uses a design of integration to overcome the problems and creates an intelligent system to process data. Some improvement methods such as the non-linear correction of meter factor, temperature and pressure compensation are proposed to improve the accuracy of flow rate. In experiments, by comparisons of the results before and after improvements, it comes to a conclusion that the intelligent integrated averaging Pitot tube flowmeter shows a higher performance.

Research of Super-Size Intelligence Flow Measurement System

In this paper, we study a kind of intelligent and high-accuracy flow measurement system, which is a type of venturi tube flowmeter that surpassed the international standard ISO5167. This paper analyzes the characteristics of the super-size flow measurement in the water transportation and industrial projects, and the choice for suitable flow meters. We study the practical compensation technology for discharging coefficient “C” of the international-standard-exceeding venturi tube, and puts forward water calibration method for venturi tube, and design the intelligent and high-accuracy flow metering system based on computer technology. Furthermore, this paper analyzes the calibration data of water flow, and propose the segment and compensation method for discharging coefficient “C” practically. We solved the limitations of the international-standard-exceeding venturi tubes, and effectively improved the accuracy and range of the flow measurement system.

A comparative study of flow rate characteristics of an averaging Pitot tube type flow meter according to H parameters based on two kinds of differential pressure measured at the flow meter with varying air temperature

A new averaging Pitot tube flow meter that has a shape similar to an Annubar® type flow meter was designed and its flow rate characteristic was evaluated. The air temperature supplied to the developed flow meter was maintained at a constant by controlling electric power supply to an electric heater during the calibration. Two kinds of differential pressure measured at the flow meter were used in calculating the H parameters, which represent characteristics of the developed flow meter. One H parameter (HΔP1) which was newly proposed in this research was calculated based on the difference between upstream pressure (stagnation pressure) at the flow meter and static pressure of the measured flow. The differential pressure is equivalent to the dynamic pressure of the flow. The other H parameter (HΔP2) which is used in a typical Annubar® type flow meter was calculated based on the difference between upstream and downstream pressure at the developed flow meters. Relationship curves between the two H parameters and the mass flow rate at the developed flow meter were obtained. The curves based on the HΔP2 parameter, which uses the difference between up and down stream pressure, show different gradients for varying the controlled air temperature. However, the other curve, based on the other HΔP1 parameter, which uses the dynamic pressure, can be represented by one linear curve even with varying air temperature.

Antimicrobial Peptides Increase Tolerance to Oxidant Stress in Drosophila melanogaster

It is well appreciated that reactive oxygen species (ROS) are deleterious to mammals, including humans, especially when generated in abnormally large quantities from cellular metabolism. Whereas the mechanisms leading to the production of ROS are rather well delineated, the mechanisms underlying tissue susceptibility or tolerance to oxidant stress remain elusive. Through an experimental selection over many generations, we have previously generated Drosophila melanogaster flies that tolerate tremendous oxidant stress and have shown that the family of antimicrobial peptides (AMPs) is over-represented in these tolerant flies. Furthermore, we have also demonstrated that overexpression of even one AMP at a time (e.g. Diptericin) allows wild-type flies to survive much better in hyperoxia. In this study, we used a number of experimental approaches to investigate the potential mechanisms underlying hyperoxia tolerance in flies with AMP overexpression. We demonstrate that flies with Diptericin overexpression resist oxidative stress by increasing antioxidant enzyme activities and preventing an increase in ROS levels after hyperoxia. Depleting the GSH pool using buthionine sulfoximine limits fly survival, thus confirming that enhanced survival observed in these flies is related to improved redox homeostasis. We conclude that 1) AMPs play an important role in tolerance to oxidant stress, 2) overexpression of Diptericin changes the cellular redox balance between oxidant and antioxidant, and 3) this change in redox balance plays an important role in survival in hyperoxia.

버터플라이 밸브의 유량측정 불확도에 대한 영향

For testing large-capacity pumps, the accurate flow rate measurement is needed in the test loop. As a measuring method of flow rate, venturi tube is recommended due to its low pressure loss. However, upstream disturbance of loop component such as a valve has an effect upon the accuracy of flow rate measurement. For controlling flow rate in case of high flow rate and large-scale piping system, a butterfly-type valve is generally used due to its compactness. However, a butterfly valve disturbs downstream flow by generating turbulence, cavities, or abrupt pressure change. In this study, the effect of downstream disturbance of butterfly valve on the flow rate measurement using a venturi tube is investigated. Test loop consists of circulation pump, reservoir, butterfly valve, venturi tube, and reference flow meter. The test is conducted with regard to a different valve opening angle of butterfly valve. According to the valve opening angle, the uncertainty of flow rate measurement is investigated.

Development of a fully automated soap flowmeter for micro flow measurements

A soap flowmeter is commonly used for measuring of low flow rates of gases. In order to have accurate measurements using this instrument, the diameter and the length of the flowmeter tube should be selected on the basis of the expected flow rate [Levy A. The accuracy of the bubble meter method for gas flow measurements. J Sci Instrum 1964;41:449–53]. However, there are restrictions when reducing the diameter of the tube or increasing its length. The objective of this study is to find alternative ways to improve the accuracy of existing flowmeters in the range of micro flow rates. To accomplish this objective a fully automated system for making soap bubbles was developed, and implemented with different commercial soap flowmeters. In addition, a computerized data acquisition was developed to improve the accuracy of the time measurement. The final product is capable of performing hands-free measurements even in isolated areas. Gas flow rates ranging from 5 to 100 μL/min were successfully measured and suggestions for more improvements in the accuracy of flow measurements are proposed. Since the automated bubble maker allows controlling the size of the soap bubbles, the modified soap flowmeter is also suitable for the investigation of free foam films in vertical tubes.

A Validated Model for the Zero Drift Due to Eddy Currents in Electromagnetic Flowmeters Operating With Electrolytic Conductors

In this paper, the author investigates theoretically the magnitudes of the zero offsets and the zero drifts originating from eddy currents in electromagnetic flowmeters operating with electrolytic conductors. The dependence of such zero offsets on the liquid properties, frequency of operation, etc., is explained. This dependence is used to predict the zero offsets expected in metering electrolytic conductors using phase sensitive detection with the flowmeter tube described in this paper. Precautions needed in flowmeter design to minimize instrument offsets and zero drifts are explained. At the end, the proposed model was validated against experimental data.

Successful flow measurement in varnish production

Measuring the flow of paint and varnish entails unique problems. Not only is the material expensive, making it essential to avoid waste, but the high-viscosity and highly pigmented raw media can impede flow. BASF Coatings in Germany found that a straight tube flowmeter manufactured by Krohne gave the best results and avoided pressure loss. Christoph Engelbert, plant and electrical engineering at BASF Coatings AG and Reiner Scheulen from Krohne Messtechnik GmbH & Co. KG, Duisburg describe the process.