Mass Flow Meter Research Articles

A novel coriolis mass flowmeter signal processing method based on adaptive notch filter and Hilbert transform

Coriolis mass flowmeter has been widely used in the energy field, and the key of mass flowrate measurement is to calculate the frequency and phase difference of the signal accurately. Aiming at the poor measurement precision problem in Coriolis mass flowmeter, a novel Coriolis mass flowmeter signal processing method is presented based on adaptive notch filter and Hilbert transform. Firstly, the long time continuous frequency tracking and accuracy problem of adaptive notch filter is effectively solved, by introducing the idea of negative feedback control. Then, the frequency estimation results are used to judgment whether the whole data will be extended or not, which makes the length of data sequence close to or equal to an integer multiple of the period. And then, Hilbert transform is conducted to the extended signals. Finally, the phase difference can be obtained by utilizing the sinusoidal functions. Simulation results show that the proposed method has high frequency and phase difference estimation accuracy, and it can be used for real time flowrate measurement of flowmeter. Experimental tests validate that the precision of this method is less than 3‰, which is more than 2 times of that of the traditional method.

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.

Experimental investigation on piston offset and performance of helium valved linear compressor with an external gas bypass

The valved linear compressor(VLC) is a significant part of the Joule-Thomson (JT) cryocooler at the liquid helium temperature zone. The use of clearance seals in the VLC inevitably causes the piston offset which affects the VLC performance and the JT cryocooler performance. Based on the VLC developed in our lab, an experimental bench for studying piston offset inhibition using the external gas bypass is built. The external gas bypass connects the compressor shell to the suction line by a bypass regulating valve which controls the mass flow, a solenoid valve that controls the number of connections and a bypass mass flowmeter which measurs the mass flow rate. The experiments focus on the effects of bypass regulating valve opening and solenoid valve action frequency on the piston offset and performance of the VLC. The experimental results show that there is an optimal opening to minimize the offset and the VLC obtains the best performance at the same time. When the solenoid valve is activated at a high frequency(greater than 1 Hz), the VLC obtains the best performance. This research provides a scheme to inhibit the piston offset by using an external gas bypass to improve the VLC performance.

An investigation of a gas–liquid swirling flow with shear-thinning power-law liquids

A gas–liquid swirling flow with shear-thinning liquid rheology exhibits complex behavior. In order to investigate its flow characteristics, experiments and computational fluid dynamics (CFD) simulations are conducted based on dimensional analysis. A Malvern particle size analyzer and electrical resistance tomography are applied to obtain the bubble size distribution and section void fraction. A Coriolis mass flowmeter is applied to obtain the mixture flow rate and mixture density for an entrance gas volume fraction smaller than 7%. The CFD coupled mixture multiphase model and large eddy simulation model are applied, considering the liquid shear-thinning power-law rheology. The results show that the swirling flow can be divided into developing and decaying sections according to the swirl intensity evolution in the axial direction. A gas–liquid swirl flow with shear-thinning liquid prohibits a core-annulus flow structure. A smaller index n contributes to maintaining the development of the swirl flow field and its core-annulus flow structure so that the swirl flow can form over a shorter distance with a stronger intensity. For a more uniform distribution of the apparent viscosity, the gas column in the pipe center is thinner. On the other hand, a larger consistency k enlarges the stress tensor. The amplitude of the velocity and the pressure of the core-annulus flow structure are reduced. A weaker swirl intensity appears with a wider gas column appearing as a consequence. Furthermore, the swirl number decays with an exponential behavior with parameters sensitive to the consistency k and index n of the decaying section of the swirling flow field. These are beneficial to gas–liquid separator design and optimization when encountering the shear-thinning power-law liquid phase in the petroleum industry.

Optimized design of the restrictor for a MEMS thermal gas flowmeter

To improve the linear range of measurement, a restrictor is usually added to the main flow channel of a capillary-tube-type thermal mass flowmeter. However, as the linear range of the flowmeter increases, the singularity will occur in the low mass flow velocity section of the flowmeter calibration data, which will lead to a significant decrease in the measurement accuracy in this section. To address this issue, first, this paper developed a microelectromechanical system (MEMS) thermal gas flowmeter based on the principle of capillary-tube-type thermal mass flow. Then, the effect of the bypass ratio on its performance was further investigated using quantitative analysis and was verified using Fluent numerical analysis. In addition, to explain the singularity, the bypass ratio-sensitivity relationship model was built. Based on this model, the bypass ratio can be changed by adjusting the restrictor parameters to optimize the performance of the MEMS thermal gas flowmeter. Moreover, six numerical simulation models of restrictors with different aperture diameters and aperture numbers were designed. The numerical analysis results show that within a certain range of aperture diameters and aperture numbers, the singularity is more easily weakened when the aperture diameter decreases or the aperture number increases. Finally, the restrictor with the optimum aperture number and suitable aperture diameter was selected as the test model for calibration, and the goodness of fit R2 of the calibration results is improved from 0.9937 to 0.9972, the singularity in the low mass flow velocity section is significantly weakened, and the sensitivity is improved.

Effects of dissipative forces on Coriolis flowmeter readings

An indirect measurement method based on recording the phase difference of resonance vibrations of two symmetrical halves of the flow-carrying tube is used to quantify the mass flow rate of the current fluid in Coriolis mass flowmeters (CMFs). A variant of modeling the CMF vibration system is analyzed, which allows taking into account the influence of the dissipation of oscillations of a measuring tube with fluid flowing through it on the dependence between the mass flow rate of the fluid and the phase difference recorded by the sensor. The steady-state CMF vibration mode is considered as the result of the superposition of two principal vibrations of the measuring tube. The first principal coordinate corresponds to the deformation of the measuring tube along the lowest natural mode excited by an external driving force in the resonance mode. Vibrations of the other principal coordinate correspond to deformation in a natural mode corresponding to a higher natural frequency than the frequency of the exciting force. The relationship of the amplitudes of the principal coordinates is established on the basis of the gyroscopic coupling of the principal vibrations that occurs when a fluid flows through a tube. The coefficients of gyroscopic coupling are determined as a result of 3D finite-element simulation of the steady-state vibration mode of the measuring tube with a flowing fluid. The simulation is performed for five variants of the shape of the axis of the measuring tube, taking into account the distribution of the gyroscopic forces of the flowing fluid. Quantitative estimates of the influence of dissipative forces on the flowmeter readings are obtained on the example of dissipative forces of linear viscous friction. A comparison of the CMF simulation results for different tube axis shapes demonstrates how the phase shift arising in the vibration system is affected by the dissipation level and the proximity of the natural frequencies of the flowmeter measuring tube at a fixed mass flow rate of the fluid.

Fiber optofluidic Coriolis flowmeter based on a dual-antiresonant reflecting optical waveguide.

A microfiber optofluidic flowmeter based on the Coriolis principle and a dual-antiresonant reflecting optical waveguide (ARROW) is proposed and experimentally demonstrated. A hollow hole in a hollow-core fiber is fabricated as an optofluidic channel to move the liquid sample, which forms a dual-ARROW in the hollow-core fiber. Two sides of the hollow-core fiber are used as two adjacent Fabry-Perot resonators based on the refractive index modulation of a CO2 laser, which is used to investigate the vibration signals of the two resonators. The flow rate can be measured based on the Coriolis force by calculating the phase difference between the two ARROWs. The experimental results show that a flow rate sensitivity of 8.04 deg/(µl/s) can be achieved for ethanol solution. The proposed micro Coriolis fiber optic flowmeter can be used in various fields, such as food production, medicine, bioanalysis, etc.

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.

A Method Applied in Anomaly Detection of Impurities Adhering to Pipes of Coriolis Mass Flowmeter

The Coriolis mass flowmeter (CMF) is widely used to measure mass flow, mainly in petrochemical, medical, pharmaceutical, food manufacturing, and other industries. The measuring tube is the crucial component of CMF, which affects the measurement accuracy and causes losses to the production of enterprises. Wall-mounted failure of the measuring tube affects measurement accuracy. A real-time detection method based on acceleration sensor array signal processing and pattern recognition are proposed to detect such failure. Two acceleration sensors are arranged outside the CMF to compose a five-channel sensor array. The signals of the multichannel array are decomposed through a blind source separation algorithm, and array signal features are extracted by a wavelet scattering network. Support vector data description (SVDD) is used to detect the hanging state of CMF at last. The experimental results show that the proposed method can be used to detect the CMF wall-mounted failure in real-time with an accuracy of 89.59%, and the method can reduce production losses.

Flow-induced vibration characteristics of the U-type Coriolis mass flowmeter with liquid hydrogen

Flow-induced vibration characteristics of the U-type Coriolis mass flowmeter with liquid hydrogen

A Novel Phase Difference Measurement Method for Coriolis Mass Flowmeter Based on Correlation Theory

Aiming at the poor precision problem in phase difference measurements with unknown frequencies in engineering practice, a new phase difference measurement method is proposed for Coriolis mass flowmeter based on correlation theories. Firstly, the signal frequency was estimated by using an adaptive notch filter, which was applied to filter the waves and determined the integer period of the sampling signals, and the non-integer period sampling signals needed to be extended. Then, the Hilbert transformation was conducted relative to the extended signals, and the correlation functions of these extended signals with the transformed signals can be computed. Finally, the formula of phase difference can be obtained by utilizing the sinusoidal function. Compared to traditional methods, such as the correlation method, the Hilbert transformation method, and sliding Goertzel algorithm, the proposed method is suitable for both integer period and non-integer period sampling signals, and its accuracy, real-time, and dynamic performance is superior. Simulation and experiment results validate the superiority and effectiveness of the proposed method.

Improved hydrogen consumption detection method with flow meter of fuel cell vehicle

With the vigorous development of fuel cell vehicles, the hydrogen consumption in the driving process of fuel cell vehicles has become a major concern of automobile manufacturers and fuel suppliers. However, the measurement accuracy of flow meter in hydrogen medium cannot meet the requirements. In this paper, computational fluid dynamics software is used to simulate the velocity distribution of water and hydrogen in Coriolis flow meter with different mass flow rates without tube vibration. Aiming at the measurement error of Coriolis flow meter, a flow calibration device based on sonic nozzle was designed, and the results of measuring hydrogen mass flow by Coriolis flow meter and thermal flow meter were calibrated. Finally, the accuracy of the calibrated flow meter for measuring hydrogen mass flow under stable and dynamic conditions is tested. The test results show that the accuracy of calibrated Coriolis flow meter for hydrogen mass flow is less than ±1%, which can meet the accuracy requirements of fuel cell vehicle hydrogen consumption measurement. This study provides an important reference for the application of flow meter method in fuel cell vehicle economic evaluation method.

In-flow measurement of the composition of a binary gas mixture

The performance of many cryocoolers that utilize the Joule-Thomson effect can be improved by using a gas-mixture as the working fluid. This paper presents a measurement setup to characterize a sorption compressor operating with a binary mixture. The composition of the binary mixture delivered by the sorption compressor is determined in-flow by correlating the outputs of a Coriolis flow meter and a thermal mass-flow meter. Based on this method, the composition of a binary mixture was measured continuously with an error of ±0.02. Multiple sorption cycles with three different mixtures of ethane and nitrogen using the same compressor were measured, allowing for the observation of the dynamic desorption behavior of a mixture.

Beam induced heat load instrumentation installed in LHC during the Long Shutdown 2

During the second run of the Large Hadron Collider (LHC) between 2015 and 2018, significant beam induced heat loads have been observed on the beam screens circuits impacting the cryogenic system capacity, mainly due to the electron clouds generated by the beams. To validate these measurements and to obtain precise heat load assessments and comparison with preliminary calculations based on existing hardware equipment at selected locations, it was decided to add new cryogenic instrumentation around the machine. In total, 23 Coriolis flowmeters (cold conditions), 4 thermal flowmeters (room temperature conditions) and 58 Cernox thermometers have been installed and commissioned between 2019 and 2021 during the so-called long shutdown 2 (LS2). This paper presents an overview of this project, including the commissioning of these instruments and confirming at first stage the original heat load estimations.

Effect of breeding temperature on enteric fermentation methane emissions in pigs

This study was conducted for the purpose of evaluating the amount of enteric fermentation methane emission from pigs according to the breeding temperature. The external structure was manufactured using flexible glass and profile, and It was made by sealing the emitted methane so as not to leak out. The inlet and exhaust were manufactured, and a ring blower was installed at the exhaust to circulate air, and the real-time flow rate was measured with a mass flow meter. Methane concentration and temperature were measured in real time using an automatic measuring system. The experimental pigs was conducted for two days at low temperature (13°C) and high temperature (25°C) on two 6-month-old fattening pigs, and feed was supplied at 09:00 am and 15:00 pm twice a day and the pigs were given free access to water. As a result of the study, the methane concentration was 14 ppm at low temperature and 21 ppm at high temperature, which was about 33% higher than that at low temperature (p < 0.05), and 6.5 g per day at high temperature (p < 0.05) and 4.6 g per day at low temperature were emitted. As a result of analyzing the dry matter digestion rate of feed intake and excreted manure, 74.08% at low temperatures and 71.10% at high temperatures, showing similar results to previous studies. Therefore, the digestivility was related to the amount of methane generated, and the lower the digestion rate, the higher the methane emission.

Calculation and judgment of repeatability error affected by non-linearity correction based on flowmeter characteristic analysis

The nonlinear characteristics of some flowmeters must be corrected so as to ensure the measurement accuracy. But the non-linearity correction may change the repeatability error between parameters, which makes the accuracy of the flowmeters fail to meet the requirements. This problem is rarely studied, but it is a basic problem. Therefore, variation of repeatability error in the non-linearity correction is deduced from the perspective of nonlinear characteristic function of the input and output. It is verified by the calibration and verification experiments of a constant-temperature-differential thermal mass flowmeter (CTDTMF). In order to facilitate engineering application, the judgment methods of piecewise linearity and relative variations of input and output are proposed, respectively, so as to quickly determine the numerical range of magnification.

The impact of placement, experimental conditions, and injections on mass flow measurements in supercritical fluid chromatography

In supercritical fluid chromatography (SFC), the variation of pressure, temperature and volumetric flow-rate is most noticeable when the mobile phase contains only neat carbon dioxide. This can be explained by the compressibility of CO2 and introduces several difficulties to the work of chromatographers. The only flow parameter that is considered to be constant across the SFC system is the mass flow-rate. It has been shown that the Coriolis flow meter (CFM) provides different types of information depending on its placement in the instrument. Therefore, the goal of this paper is to investigate several factors affecting the variation of mass flow-rate in SFC, including four different configurations around the column, four sets of experimental conditions along with two columns and a zero-volume union. The effect of disturbances introduced by injections are studied as well. The results show different mass flow-rates when taken at the inlet or the outlet of the column. In addition, different columns produced different tendencies of variations. Study of the injections showed that the initial severe drop of mass flow is reduced when the averages are taken until the elution times of the chosen compounds. Additional testing related to possible leaks and CFM calibration showed that even if all standard operating procedures are strictly followed, reproducibility of the mass-flow rate can still be an issue.

Methanation of Synthesis Gas to Produce Methane: A Hands-On Catalysis Experiment

Organizing undergraduates in chemistry, energy engineering, and chemical engineering specialties to participate in an energy transformation experiment can encourage them to think about the impact of human activities on nature and stimulate them to learn more about the topic. This laboratory experiment demonstrates a general approach to the methanation of syngas in a fixed bed reactor with online chromatographic monitoring. Undergraduates gain the opportunity to operate temperature controllers, mass flow meters, fixed bed reactors, gas chromatography, and cold traps as well as broaden their knowledge of renewable CO/CO2 conversion. The experiment also offers a discussion about the chemical principles in catalytic conversion of syngas to methane, viable alternatives to green fuel sources, and the catalytic reaction process.

Development of a high-fidelity partitioned Fluid–Structure Interaction model of an Omega-shaped Coriolis Mass Meter and comparison with experimental data

Coriolis Mass Meters (CMMs11Such measurement devices are usually regarded as either Coriolis Mass Flow-meter (CMF) or Coriolis Flow-meter (CFM) or Coriolis Mass Meter (CMM). In this work, the latter naming is used.) are devices for measuring the mass flow rate of a flow in a pipe by a mechanism based on exciting a specific mode shape of the flow-meter’s structure and analyzing the system’s response to the interaction between the vibrating CMM’s structure and the flow. This interaction manifests itself as a phase-shift between the signals captured by the motion detection sensors, located on the CMM’s structure. By design, a characteristic of the CMMs is the linear relation between the induced phase-shift and the mass flow rate in a wide range of flow regimes. Due to the complexity of such dynamic systems, low-fidelity numerical models are often not capable of capturing the relevant physics and, therefore, cannot be relied on in the design process of the CMMs. The goal of this paper is to develop a physically significant and reliable high-fidelity Fluid–Structure Interaction (FSI) model of Omega-shaped CMMs which can be used in the virtual design scenarios. Such a model is useful for e.g. parametric studies and importance rating of parameters. In order to achieve that goal, different modeling aspects, simulation and post-processing techniques are systematically assessed. The result is a numerical model based on strongly coupled partitioned FSI between the CMM’s structure and the fluid passing through it. Both fluid and structural domains are discretized using finite element method (FEM). The induced phase-shift due to FSI is calculated for a range of mass flow rates. It is verified that the calculated phase-shift from the simulations varies linearly with the mass flow rate. Furthermore, the numerical results are compared to and are in good agreement with experimental results. Hence, the developed high-fidelity model is shown to be accurate enough to be used for designing and enhancing the performance of Omega-shaped CMMs, affirming the relevance of the thoroughly discussed modeling aspects.

임계점 부근의 이산화탄소-메탄 혼합물의 관내 응축 열전달 특성 연구

The condensation heat transfer coefficient and pressure drop for pure CO₂ and CO₂+CH₄ mixture were investigated under the near-critical condition, which simulates the CO₂ transporting conditions under Carbon Capture and Storage (CCS) process. The experimental facility consisted of a test section, heat exchangers, mass flow meters, temperature sensors, a magnetic gear pump, and a differential pressure transducer. The test section made with a copper tube was assembled with Polyvinyl Chloride (PVC) pipe to form a double tube. The condensation temperature and mole fraction of CH₄ in the CO₂ mixture ranged from 20℃ to 30℃, and 1% to 5%, respectively. The mass flux was changed from 500, 600, and 700 kgm-2s-1. The two-phase flow pattern under the set conditions was estimated to be the annular flow. When the mole fraction of methane in the mixture increased from 1% to 5% at 20℃ of condensation temperature, the average condensation heat transfer coefficients and the pressure drop for CO₂+CH₄ decreased from 4.97% to 19.9%, and 30.0% to 54.5%, respectively, compared to those for pure CO₂