Flow Measurement Method Research Articles

Flow measurement based on the combination of swirler and differential pressure under slug flow

The alternating appearance of elongated bubbles and liquid slugs of slug flow in the pipe causes severe pressure fluctuation. As a result, measuring the flow rate of the slug flow with the throttling unit based differential pressure method is difficult. This paper investigates a new swirler-based flow measurement method in slug flow. The swirler converts the slug flow into a swirling annular flow, and the differential pressure method is used to measure the flow rate. The influences of gas and liquid flow rates on the differential pressure ΔPX across the swirler as well as its downstream axial differential pressure ΔPZ are investigated. ΔPX0.5 increases linearly as the liquid mass flow rate increases, and the slope of the curve increases as the gas mass flow rate increases. The influence of gas mass flow rate on ΔPX0.5 is comparable to that of liquid mass flow rate on ΔPX0.5. ΔPZ0.5 increases linearly with increasing gas/liquid mass flow rate, and the slope of the curve of ΔPZ0.5 with ml differs slightly from the slope of the curve in single-phase water conditions. Based on the research presented above, new empirical correlations of mass flow rate based on ΔPX and ΔPZ are established respectively. The superficial liquid velocity ranges from 0.6 to 2 m per second, while the superficial gas velocity ranges from 2 to 6 m per second. If the gas mass flow rate and ΔPX are known, the relative error of liquid mass flow is less than 3%. The relative error of the gas mass flow rate is less than 10% if the liquid mass flow rate and ΔPX are given. The calculation accuracy of the flow measurement model using ΔPX is better than the calculation accuracy of the flow measurement model using ΔPZ.

Numerical and experimental flow investigation using ultrasonic PIV for optimizing mechanically agitated lab-scale anaerobic digesters

In this article, a non-invasive ultrasonic flow field measurement method is studied to investigate its applicability to resolve fluid flow in bio- and chemical engineering reactors. In detail, the proposed flow field investigation method is applied to mechanically agitated lab-scale reactors for the validation of anaerobic digester mixing simulations. Two reactors with different geometries, which are cold models of real-life anaerobic digesters, are studied. Since conventional non-invasive flow field measurement techniques are not suitable for the investigated reactor geometries, the applicability of ultrasonic measurement is demonstrated. The experimental results are compared to Computational Fluid Dynamics (CFD) simulations using the Finite Volume Method with multiple reference frames to account for the stirrer-induced mixing. It is shown that ultrasonic measurement is an easily applicable non-invasive method for resolving flow fields of opaque fluids found in chemical, mechanical and biological engineering. The study highlights the benefits of the non-invasive measurement approach and also demonstrates the suitability of this flow measurement technique for further applications such as the optimization of the mixing time characteristics of paints and coatings or silicone production. The resolved flow fields are in accordance with numerical reference results with minor deviations of up to 9% for velocity measurements aligned with the main axis of the ultrasound probe. The validated CFD model can be used as a template for modelling similar chemical engineering processes where the mixing time characteristic is critical. It is further shown that the accuracy of this flow measurement method decreases with increased offsets from the main axis. In addition to the axis alignment, the impact of different fluid properties and reactor geometries is also discussed.

Analysis of Azimuthal Doppler Shift of Anisotropically Absorbed Laguerre-Gaussian Beam Propagating in Transverse Flow

The particle flux onto a material is an important parameter in the study of the plasma-material interaction. With conventional Doppler spectroscopy, it is difficult to measure the flow velocity perpendicular to the material because only the velocity component projected on the wave number vector can be measured. To overcome the limitation, we are developing a transverse flow measurement method using the azimuthal Doppler shift of a Laguerre-Gaussian (LG) beam absorption spectroscopy. In this paper, the feasibility of this spectroscopy method has been examined by numerical analysis. The LG beam is anisotropically absorbed in the transverse flow due to the azimuthal Doppler shift. Since the anisotropic LG beam rotates with propagation, the spatial structure of resonance absorption in plasma and the intensity structure of the LG beam that has propagated through the plasma are inevitably different in the LG beam absorption spectroscopy. It was shown that the deviation from the original azimuthal Doppler shift is reduced to several percent at the position where the intensity distribution of the LG beam reaches its maximum value. Therefore, the transverse flow can be measured with sufficient accuracy by properly selecting the position on the beam cross-section used to evaluate the azimuthal Doppler shift.

Nailfold capillaroscopy: tips and challenges.

Although nailfold capillaroscopy (NFC) appears to have a bright future in clinical practice, the lack of familiarity with the technique and how to interpret its outcomes is major barriers which have made nailfold capillaroscopy an underutilized method in standard clinical practice. Traditional methods for assessment and measurement of capillary patterns, density, and blood flow are falling behind and face some challenges. In fact, there have been calls for improvement, hence the recent publication of the standardization of NFC by the EULAR Study Group on Microcirculation in Rheumatic Diseases. Nailfold capillaroscopy has the advantage of being a non-invasive technique that provides a window into the digital microcirculation. This paved the way for a rapidly growing interest in using capillaroscopy parameters as outcome measures in research. In standard clinical practice, whilst its main application is in the identification of an underlying systemic sclerosis spectrum disorder in patients presenting with Raynaud's phenomenon, its use has expanded to include other clinical features possibly suggestive of an underlying connective tissue disease. This article presents the challenges, provides tips, and highlights the exciting potential of nailfold capillaroscopy in standard practice.

Flow velocity sensors arrangement for vegetated channels.

Ecological rivers or ecological channels are being widely used. Precious measurement and estimation of flow in irrigation areas are important issues in agricultural engineering. For the sustainable development of vegetation, it is necessary to consider how to use sensors to measure flow more easily in the river to protect both plants and sensors from damage. This article selects smooth channels and ecological channels of different shapes for research and presents a simplified method for arming ultrasonic sensors to obtain channel flow velocity. The flow characteristics along the normal line direction are obtained by theoretical analysis. The method uses the average flow velocity based on the normal to the channel wall to determine the location of the sensors. It combines the flow velocity determined by the sensors with the flow calculation method, thus simplifying the flow estimation steps. Experiments under flow conditions validate the efficacy of the proposed ultrasonic sensor arrangement method. This article not only simplifies the arrangement of sensors in channel flow but also improves the accuracy of the flow measurement method, which is important to promote the construction of ecological channels.

A Bayesian estimation method for cerebral blood flow measurement by area-detector CT perfusion imaging.

Bayesian estimation with advanced noise reduction (BEANR) in CT perfusion (CTP) could deliver more reliable cerebral blood flow (CBF) measurements than the commonly used reformulated singular value decomposition (rSVD). We compared the efficacy of CBF measurement by CTP using BEANR and rSVD, evaluating both relative to N-isopropyl-p-[(123) I]- iodoamphetamine (123I-IMP) single-photon emission computed tomography (SPECT) as a reference standard, in patients with cerebrovascular disease. Thirty-one patients with suspected cerebrovascular disease underwent both CTP on a 320 detector-row CT system and SPECT. We applied rSVD and BEANR in the ischemic and contralateral regions to create CBF maps and calculate CBF ratios from the ischemic side to the healthy contralateral side (CBF index). The analysis involved comparing the CBF index between CTP methods and SPECT using Pearson's correlation and limits of agreement determined with Bland-Altman analyses, before comparing the mean difference in the CBF index between each CTP method and SPECT using the Wilcoxon matched pairs signed-rank test. The CBF indices of BEANR and 123I-IMP SPECT were significantly and positively correlated (r = 0.55, p < 0.0001), but there was no significant correlation between the rSVD method and SPECT (r = 0.15, p > 0.05). BEANR produced smaller limits of agreement for CBF than rSVD. The mean difference in the CBF index between BEANR and SPECT differed significantly from that between rSVD and SPECT (p < 0.001). BEANR has a better potential utility for CBF measurement in CTP than rSVD compared to SPECT in patients with cerebrovascular disease.

Time-Averaged And Time-Resolved Laser Optical Temperature Measurements In Water With Filtered Brillouin Scattering Combined With LDV

A laser measuring system was developed and built that allows to optically measure temperature in water using the method of Filtered Brillouin Scattering (FBS). First time-resolved optical temperature measurements were demonstrated. Furthermore, the FBS-system was combined with an LDV to enable simultaneous measurement of flow velocity and therefore the system is also capable to measure the heat flow. Time-averaged temperature values were determined with good accuracy and, as a special highlight, also time-resolved temperature measurements have been demonstrated with temporal resolution in the order of approximately 10 ms, validated by comparison with fast thermocouple measurements. The overarching goal of the research project was to prepare the market introduction of a laser-optical measuring system for spatially point-based and time-resolved measurement of the heat flow in liquids, especially in water. In order to realize this, it was necessary to measure the local velocity and the local temperature in a liquid. The optical measurement of the local velocity has long been possible using the established method of laser Doppler velocimetry (LDV). Therefore, the heat flow measurement method to be developed should be based on this technology. Until now, there was no suitable optical method for measuring the temperature. In recent years, however, the physical phenomenon of Brillouin scattering has become one focus of measurement technology development. If a small volume of liquid is irradiated with light, the molecules in the liquid scatter back part of the light, which is known as Brillouin scattering. The spectrum of the scattered light depends on the local temperature in the liquid; and it turns out that this physical relationship can be exploited to develop a highly accurate, fast, and non-contact method for measuring temperature. In this paper, we explain the Filtered Brillouin Scattering (FBS) method, show a setup for measuring temperature and velocity in water flows and thus a method for determining the heat flow, and demonstrate the measurement accuracy using a calibration test bench. The temperature measurement accuracy achieved is in the order of 1 K.

439 Vessel-Specific Quantitative Flow Measurement With A Low-Dose Comprehensive Cardiac CT Technique Versus 82Rb PET - Preliminary Validation In Human Subjects

Introduction: This study validated a novel comprehensive cardiac CT technique that combines coronary CT angiography (CTA) with a new single-volume quantitative CT flow method for low-dose, vessel-specific, quantitative rest and stress flow measurement as compared to 82Rb PET.

Improving Effectiveness of Flow Measurement by Bypass Method: A Technique Applied to Thermal Mass Flowmeter

Abstract Fluid velocity or flow rate measurement, by flow sampling or bypassing flow from main pipelines, offers several advantages, like reducing the footprint of the flowmeter and avoiding the stoppage of a process during flowmeter repair or replacement. The flow measurement technique could be thermal mass flowmetry, a popular flow measurement method. A major limitation in the bypassing technique is the low flow rate through the bypass pipe resulting in a weak flowmeter thermal signal or reduced sensitivity to flow. This paper describes the usage of a validated computational fluid dynamics (CFD) model to investigate several bypass pipe designs to maximize fluid flow rate through the bypass pipes installed on the main pipeline and consequently maximize the thermal signal generated by an elementary thermal mass flowmeter installed on the bypass pipe. Investigations reveal that bypass design modification can improve thermal signal strength by as much as 38% with respect to that obtained in the baseline bypass design.

Comparison of Methods for Elliptic Flow Measurements at NICA Energy Range

Comparison of Methods for Elliptic Flow Measurements at NICA Energy Range

A novel concept of automatic soap flowmeter with bubble detection by closing an electrical circuit

A novel accurate method of automatic timing of bubble motion through the measuring section of a soap flowmeter is proposed. The method is based on the closure of an electrical circuit by a soap bubble moving in the calibrated tube. The accuracy of the automated flowmeter, estimated by comparison with other accurate flow measurement methods, is found to be 2%. Modification of the bubble making system aimed at increasing of the flowmeter tightness and bubble quality is developed, as well. The proposed design does not require precise assembly and admits the use of cheap and readily available components.

Development of Gas-Liquid Two-Phase Flow Measurement Method Using Multi-View Camera System

Although there exist several methodologies to measure gas-liquid two-phase flows, such as wire-mesh sensors and X-ray CT, a direct measurement of bubble coalescence and breakup is difficult due to their multidimensionality and unsteady nature. However, a comprehensive understanding of gas-liquid two-phase flow under such conditions is essential for predicting the effectiveness of scrubbing, i.e. to remove fission products during severe accidents in nuclear power plants. The objective of this study is to develop a new methodology to directly measure and analyze gas-liquid two-phase flow under high void, churn-turbulent regime in a large space through an initially stagnant pool of water. For this purpose, a new technique to measure two-phase flow using multi-view images has been developed. A total of 29 synced cameras housed in a water-proofed casing were placed inside a test section with an inner diameter of 1.5 m and a height of 4 m, to construct a multi-view camera system. The test section was filled with water up to a height of 2 m, and images were taken as air was supplied from a cylindrical nozzle at the bottom with flow rates of 500 to 2000 L min-1. The cameras were calibrated, and an algorithm was developed to reconstruct the air flow in 3D voxel space. The results suggest that the developed technique, together with data assimilation and other techniques, could be applicable for measuring gas-liquid two-phase flow under churn-turbulent regime in a large space. In this paper, the progress of the development of the multi-view measurement and analysis technique, and the results of preliminary investigations are discussed.

Gas Flow Measurement Method with Temperature Compensation for a Quasi-Isothermal Cavity

Pneumatic transmission is a technology that uses compressed air as a power source to drive and control various mechanical equipment to realize the mechanization and automation of production processes. With the development of industrial mechanization and automation, pneumatic technology, represented by pneumatic muscle, is increasingly becoming more widely used in various fields. The current standards for research are more complex for the measurement of flow without a flowmeter, some of them do not consider the influence of temperature change on flow measurement, and some of them are simplified as adiabatic or isothermal models, which are inaccurate measurement methods in actual practical application. This paper describes a method to determine flow rate by measuring the pressure change in the process of gas tank inflation. This study used the method of temperature compensation to eliminate the influence of temperature in the isothermal formula. The measurement structure was simple and the calculation was accurate, which has a certain practical significance. Based on this method, charging experiments were carried out with a gas tank that had a volume of 3 L or 5 L with or without copper wire filling, and the experimental results were used in the processed research. The temperature compensation parameters were identified with or without an isothermal environment and in different sizes of tanks. This method identified the different parameters of the 5 L tank and 3 L tank. Finally, the flow compensation was completed for the gas tank filled with copper wire. After verification, the results of the quasi-isothermal calculation formula and temperature compensation formula were close to those measured by a high-precision flow sensor in the experiment. The method introduced in this study is a novel flow calculation method that is simple in structure and accurate in calculation compared with the conventional isothermal calculation method; furthermore, it can be used in real world situations without the need for a high-precision flow sensor.

A Small Flow Point Signal Processing and Measurement Method for Ultrasonic Gas Meter

A Small Flow Point Signal Processing and Measurement Method for Ultrasonic Gas Meter

Final activity report of the “Workshop of Advanced Studies for Steam Flow Measurement”

The "Workshop of Advancement of Steam Flow Measurement" started its activities in April 2017 within the Power and Energy Systems Division of the JSME and finished as planned in March 2022. The industrial sector has a steam demand of 1.12 million TJ/year, which is the second largest energy source after electricity, and steam accounts for about 80% of the heat energy use in the industrial sector and is widely used in large quantities in the main production processes: sterilization, drying, cleaning and distillation. Steam is thus a major heat source in the industrial sector and there is a strong need for flow measurement from the perspective of energy conservation. However, flow measurement of steam is very difficult due to its high temperature and susceptibility to wetness. In addition, there are very few measurement standards. Therefore, the study group has made efforts to clarify the condition of application and accuracy of each measurement method with regard to the flow measurement method of steam. The number of committee members is 30 (chief: Shuichi Umezawa (Tokyo Electric Power Company Holdings, Inc.), vice-chair: Ryo Morita (Central Research Institute of Electric Power Industry), secretary: Tatsuya Funaki (National Institute of Advanced Industrial Science and Technology)), who come from universities, companies, research institutes and others. The frequency of its activities is as follows: it holds study groups once or twice a year, summarizes its results and publishes a report. The predecessor of this study group, the "Workshop of Wet Steam Flow Measurement" (April 2012 - March 2017), also published a report summarizing its overall activities. On the basis of these results, an academic standards development committee has been set up this year and is preparing guidelines for the correction of wet steam flow rate indications from the perspective of thermal energy utilization.

Transpiration and water use efficiency of maize in different soil moisture conditions

Abstract Globally, agriculture accounts for 80–90% of the fresh water used by humans, and in many crop production systems; this water use is unsustainable. Irrigation of large areas of field and horticultural crops is impossible. Studies of the impact of drought on important field and horticultural crops are necessary to estimate dimensions of adaptation and mitigation measures to climate change. For this purpose, maize was monitored as a model crop in this study. In a three-year experiment (i) using the sap flow measurement method, the transpiration of maize was evaluated during flowering and grain filling, (ii) water use efficiency (WUE) was evaluated in four soil moisture conditions. The intensity of transpiration was closely correlated with the values of global radiation and vapor pressure deficit. However, soil water content was a major factor influencing transpiration under drought stress. The transpiration decreased when water content in the soil reached 28% of available water holding capacity (AWHC), but the yield of corn cobs decreased only under stress of 25% AWHC. Thus, the yield reacted less sensitively to lower water availability than transpiration. WUE increased with decreasing transpiration. Statistically significantly higher WUE was already observed at a water content of 42% AWHC, however, a higher WUE did not lead to a higher yield of corn cobs.

Doppler ultrasound to assess the pharmacodynamic effects of splanchnic vasoactive compounds.

In search of noninvasive biomarkers to assess the pharmacodynamic effects of portal pressure-lowering drugs, the reproducibility of flow measurements in the superior mesenteric artery was evaluated using Doppler ultrasound. A reproducibility study was conducted in 15 healthy male volunteers (18-50 y). Eight ultrasound measurements were performed for each subject: 2 observers each conducted 2 measurements during 2 separate visits. The following flow parameters were captured: peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index (PI), volume flow (VF) and vessel diameter. Reproducibility was assessed by the intraclass correlation coefficient. Results are presented as intraclass correlation coefficient [95% confidence interval]. The flow parameters PSV, EDV, PI and VF correlated excellently within observer during visit 1 (0.888 [0.748-0.953], 0.910 [0.793-0.962], 0.844 [0.656-0.933] and 0.916 [0.857-0.951], respectively) and visit 2 (0.925 [0.829-0.968], 0.942 [0.863-0.976], 0.883 [0.719-0.954] and 0.915 [0.855-0.951], respectively). Measurements conducted during 2 separate visits by 1 observer correlated well to excellently for PSV, EDV, PI and VF (0.756 [0.552-0.875], 0.836 [0.694-0.916], 0.807 [0.631-0.904] and 0.839 [0.783-0.882], respectively). Measurements conducted by 2 distinct observers correlated well to excellently for PSV, EDV and VF during visit 1 (0.813 [0.584-0.922], 0.884 [0.597-0.945] and 0.786 [0.575-0.899], respectively) and visit 2 (0.779 [0.498-0.912], 0.861 [0.672-0.945], 0.810 [0.553-0.926], respectively). Vessel diameter measurements were poorly reproducible. Doppler ultrasound is a reproducible method for flow measurements in the superior mesenteric artery in a standardized group of healthy volunteers. Therefore, it is a promising technique to assess pharmacodynamic effects of splanchnic vasoactive compounds in early clinical drug development.

Particle Image Velocimetry for in vitro characterization of Paravalvular Leakage of TAVR-sealing concepts

Abstract Paravalvular leakage (PVL), defined as the leakage between the aortic annulus and a transcatheter aortic valve replacement (TAVR), is verifiably associated with short- and long-term clinical outcome, especially with increased mortality. Therefore, with the ambition to reduce or even prevent PVL of next generation TAVR, it is necessary to extend the hemodynamic understanding of PVL. This study presents an in vitro flow measurement method to localize PVL during hydrodynamic characterization of TAVR and furthermore presents different design features, socalled outer skirt, to reduce PVL. Particle image velocimetry (PIV) measurements were performed for flow field assessment during hydrodynamic characterization of TAVR. Additionally, two different sealing concepts were developed to reduce PVL. The skirts were manufactured from polymeric-nonwoven and sued to pericardium-based TAVR-prototype. The prepared TAVR-prototypes were then deployed in a pathophysiological model of the aortic root with a calcification nodule of 2 mm according to ISO 5840:2021. To assess PVL, the flow field and the regurgitation volume was measured. The PIV measurements showed a clearly visible leakage jet between the TAVR-prototypes without skirt and the pathophysiological aortic annulus model. Jet velocities of up to 0.5 m/s were measured depending on presence or configuration of a PVL-preventing skirt. When implanted in the physiological annulus model without calcification nodule, PVL was hardly recognizable. The regurgitation volume of a TAVR-prototype without skirt at 5 l/min was 36.26±1.89 ml (n = 10). The developed and manufactured polymeric-nonwoven skirts reduced PVL from 37.67±1.17 ml to 18.36±1.8 ml (n = 10, TAVR-skirt-design1) and from 46.97±1.07 ml to 17.85±1.29 ml (n = 10, TAVR-skirt-design2) at 5 l/min. The localization of PVL during hydrodynamic characterization by means of PIV was successful. The sealing concepts developed in this work were very effective and led to a PVL-reduction of the tested TAVR prototypes of about 50% to 70%.

Maximum heat ratio: bi-directional method for fast and slow sap flow measurements

BackgroundAs sap flow research expands, new challenges such as fast sap flows or flows co-occurring with freeze/thaw cycles appear, which are not easily addressed with existing methods. In order to address these new challenges, sap flow methods capable of measuring bidirectional, high and slow sap flux densities (Fd, cm3 cm−2 h−1), thermal properties and stem water content with minimum sensitivity to stem temperature are required.PurposeIn this study we assessed the performance of a new low-power ratio-based algorithm, the maximum heat ratio (MHR) method, and compare it with the widely known heat ratio (HR) method using a cut-tree study to test it under high flows using Eucalyptus grandis trees, and a freeze/thaw experiment using Acer saccharum trunks to test its response to fast changing stem temperatures that result in freeze/thaw cycles.ResultsOur results indicate that MHR and HR had a strong (R2 = 0.90) linear relationship within a Fd range of 0–45 cm3 cm−2 h−1. Using the MHR algorithm, we were able to estimate wood thermal properties and water content, while extending the measuring range of HR to approximately 0–130 (cm3 cm−2 h−1). In our freeze/thaw experiment, the main discrepancy between MHR and HR was observed during freezing, where HR had consistently lower Fd (up to 10 cm3 cm−2 h−1), with respect to MHR. However, both algorithms identified similar zero flows.ConclusionConsequently, MHR can be an easy-to-implement alternative algorithm/method capable of handling extreme climatic conditions, which can also run simultaneously with HR.

Simultaneous Measurement of Two-Phase Flow Parameters for Drift-Flux Model

The drift-flux model is widely used in study, calculation and design of two-phase flow. It is a highly efficient model that requires little computation resources. In the model, accurate calculation of the distribution parameter C0 and the drift velocity Vgj is a critically important factor. The calculation requires simultaneously measured data of phase velocity and void fraction distributions or profiles. By using currently widely used methods for two-phase flow measurement, satisfying the requirement is highly difficult. This paper presents novel results of simultaneous measurement of the phase velocity and void fraction profiles in a vertical round tube of 50 mm inner diameter. A combination measurement method has been developed. It comprises the multiwave Ultrasonic Velocity Profile (multiwave UVP) method and the Wire Mesh Tomography (WMT). Based on the measured data, C0 and Vgj have been calculated. They have been compared with those of the published experimental data and correlations. Analyses of the measured data have been carried out. For the first time, the analysis results reveal the variation of C0 and Vgj in the measured flow conditions. More importantly, the data obtained are also useful for the development and validation of the computational codes for two-phase flow.