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![Simplified block diagram of the sensor and measuring electronics and the timing diagram for the multiplexed excitation and measuring scheme for the sensor. Circuit and timing are based on [58].](profile/Chao-Tan-6/publication/347336986/figure/fig7/AS:1009779086471171@1617761503593/Simplified-block-diagram-of-the-sensor-and-measuring-electronics-and-the-timing-diagram.png)
Simplified block diagram of the sensor and measuring electronics and the timing diagram for the multiplexed excitation and measuring scheme for the sensor. Circuit and timing are based on [58].
Source publication
Multiphase flow is a commonly seen transient and complex dynamic system in many industrial processes. The phase fraction and velocity are two of the most important parameters for flow monitoring and measurement. Due to the advantages of simplicity in sensor structure, low fabrication costs and fast response, conductance sensors have received broad...
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Context 1
... gas-liquid flow visualization [52] and was seen as hybrid solution in between intrusive probe and tomographic imaging. The sensor comprises of two set of wires (emitters and receivers) stretched over the cross section of a vessel or pipe. Each plane of parallel wires is positioned perpendicular to each other, thus forming a grid of electrodes. Fig. 8 depicts a simplified block diagram for a hypothetical 33 wire-mesh sensor. The signal is sampled at the rising edge of the sample-and-hold signal. One frame is complete when the 3 transmitter electrodes have been activated and all currents have been measured. Besides, the timing diagram illustrates the signals for multiplexed ...
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... all crossing points. Transmitter electrodes area activated individually and sequentially while non-activated wires are grounded, to concentrate the electrical potential along a transmitter wire. The current flowing towards receiver wires are converted into voltages and analog-to-digital converted on the rising edge of the sample-and-hold signal (Fig. 8). The wire-mesh subdivides the pipe cross section into several subregions which are individually sampled. In this way, a multiplexed probing-sensing schema allows to obtain images of cross section phase distribution at high repetition rates (up to 10,000 frames per second [53]). Based on raw data and knowing the electrical properties of ...
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Citations
... Conductivity probes with different electrode geometry are widely used for flow pattern identifications [6], [7], phase fraction calculation [8], [9], velocity [10], and flow rate measurement [11]. The intrusive sensors (e.g., parallel wire, needle probe) provide better sensitivity due to the capture of local instantaneous flow characteristics [12]. On the other hand, nonintrusive conductivity probes (flush-mounted arc or ring-type probes) overcome the problem of flow disturbance caused by the previous one. ...
A simple measurement scheme is proposed to reconstruct the geometry of an axisymmetric void propagating through a conducting liquid using a pair of parallel wire conductivity probes. An experimental study allows for obtaining the time variation of the resistance of the film surrounding the void. Analytical modeling and numerical simulation has been adopted to correlate the resistance between the wire electrodes and the film thickness. Finally, the shape of the void can be estimated by combining the predicted resistance–film thickness relationship and the measured time variation of resistance. For validation, this scheme has been used to reconstruct the shape of a rising Taylor bubble. There is a fair match between the reconstructed shape of the bubble and its photographic image. The probable errors in the measurement scheme have been discussed and assessed mathematically.
... The spacing between the exciting and measurement electrodes s = 5 mm and the width of the electrodes w = 1 mm. For the excitation frequency, to safety eliminate the influence of parasitic capacitance at high frequencies and avoid aging effects at electrodes due to electrochemical processes at low frequencies [21], while meanwhile maintaining a strong anti-interference ability, an excitation frequency of 100 kHz is chosen in this study. The ring conductance sensor is calibrated by a planar electrode calibration device based on the voltage equivalent principle. ...
Based on a conductance-vortex meter dual-modality system, a novel wet gas flow measurement method is proposed, which combines a vortex meter with disturbance wave frequency. A negative relationship between the vortex signal quality and the disturbance wave frequency is found, on which basis a new segmented fast Fourier transform–continuous wavelet transform vortex frequency extraction method is proposed. Uniform exponential equations are derived for meter over-reading, taking into account the liquid-phase Reynolds and gas-phase Weber numbers, the disturbance wave Strouhal number, density ratio, and the liquid-phase Reynolds number. Finally, a Newton–Armijo-based wet gas metering model is developed by combining these two correlation equations. The percentage errors (PEs) of the gas flow in wet gas are within ±1.0% error bands with uncertainty of 0.56%. The full-scale PEs of liquid flow are within ±10% error bands with uncertainty of 4.71%. The disturbance wave frequency is used to correct the meter over-reading. As no liquid film thickness calibration is needed, the proposed method has low requirements on the conductivity of the medium and hence the application scope of media could be expanded.
... Conductivity probes with different electrode geometry are widely used for flow pattern identifications [6], [7], phase fraction calculation [8], [9], velocity [10], and flow rate measurement [11]. The intrusive sensors (e.g., parallel wire, needle probe) provide better sensitivity due to the capture of local instantaneous flow characteristics [12]. On the other hand, nonintrusive conductivity probes (flush-mounted arc or ring-type probes) overcome the problem of flow disturbance caused by the previous one. ...
A unique measurement scheme for determining the shape of an axisymmetric bubble propagating through a non-conductive liquid is proposed. The method employs a set of parallel wire capacitive probes capable of measuring the thickness of the dielectric layers between the electrodes. First, the probe capacitance has been determined in terms of void fraction and the electrode geometry through a theoretical calculation. A 3D numerical simulation has also been performed to estimate the probe capacitance with varying liquid film thickness. The time-varying probe response and the propagation velocity of the void are obtained experimentally. Then the developed electrodynamic models, with the help of the above two information, estimate the film thickness profile and reconstructs the void geometry. A comparison with the photographic image of the bubble reveals that the numerical method yields a better match than the theoretical model.
... Multiphase flow is a term used to describe the flow of two or more fluid phases, such as gas and liquid, within a single pipeline or vessel (Nazeer et al., 2022). These systems are ubiquitous in various industrial processes, such as oil and gas production, chemical processing, and nuclear reactors, and pose several challenges in terms of modeling and design (Balachandar et al., 2020;Lube et al., 2020;Roshani et al., 2021;Shi et al., 2021). Two-phase flow, a specific type of multiphase flow, refers to the simultaneous flow of two immiscible fluids, such as gas and liquid (Nazeer et al., 2022). ...
Two-phase flow regime identification is an essential transdisciplinary topic that spans digital signal processing, artificial intelligence, chemical engineering, and energy. Multiphase flow systems significantly impact pipeline safety, heat transfer, and pressure drop; therefore, precisely identifying the governing flow regime is crucial for effective modeling and design. However, it is challenging due to the geometrical complexity of flow regimes in multiphase flow. With the advances in sensor measurement and machine learning, applying non-destructive tests and self-supervised learning to practical industrial problems has become technically feasible and cost-effective. This study applies a weak-supervised learning-based two-phase flow regime identification solution using a non-destructive tests ultrasonic sensor in an S-shape riser experimental bed by proposing a self-supervised feature extraction algorithm. The proposed self-supervised feature extraction algorithm reduces time/labor consumption and human error in data annotation using SSL, which provides full supervision without manual annotation. The self-supervised feature extraction algorithm uses a bottlenecked neural network and encoder-decoder structure to extract compact features. The self-supervised feature extraction algorithm performance is evaluated using an established convolutional neural network-based classifier. The source data was collected from a 10 × 50 m riser experimental rig. The dataset is made available to the community as part of this study. The performance of the approach is comparable with state-of-the-art methods and is also the first successful attempt to apply self-supervised learning to multiphase flow regime ultrasonic signal identification. This study achieved 98.84%, 0.000663, 0.00312, and 7.71 × 10 5 in accuracy, root mean square error, categorical cross-entropy, and model complexity, respectively. The practical experiment justifies the robustness, fairness, and practicability in the practical application environment. The proposed self-supervised feature extraction brings new approaches and inspirations for the feature extraction step in identifying a two-phase flow regime, and it will be beneficial to generalize this study in different riser shapes in the future.
... There have been numerous review articles so far on conventional multiphase flow due to its profound scientific and engineering significance. However, most of them are devoted to a specific aspect, such as multiphase microfluidics [24][25][26], nanofluidics [27][28][29], fuel cells [30,31], multiphase flow in porous media [32,33], flow corrosion mechanism in pipes [34], and complex flow measurement technology [35][36][37]. Until now, there has been no comprehensive work to summarize the RTLMs multiphase flow physics. Such an endeavor would help stimulate insights into various potential aspects of RTLMs multiphase flow and facilitate collaboration among researchers and practitioners across disciplines. ...
Multiphase flow existing everywhere in the motion evolution of nature, industrial processes, and daily life, has been an interdisciplinary cutting-edge frontier covering rather diverse disciplines. Traditional multiphase flow of high melting metals typically involves gas/vapor-liquid two-phase fluidics which usually requests intense energy processes and therefore limits their applications to a large extent. From an alternative, the newly emerging room-temperature liquid metals (RTLMs) with fascinating metallic fluidic properties and multifunctional behaviors, not only well resolves the existing challenges facing conventional technologies, but also opens up a series ofnew scientific and engineering subjects. Especially, the conceptual introduction of multiphase composites endows liquid metal with many unconventional fluidic capabilities. To further push forward the advancement of this new area, the present article is dedicated to systematically outlining the scientific category of RTLMs multiphase flow physics and interpreting its fundamental and practical issues. The vision is to provide insights into promising developmental directions of RTLMs multiphase flow and thus facilitate synergetic research and progress among different disciplines. First, the traditional metal multiphase flow was briefly introduced. Then, we summarized the physics of RTLMs multiphase flow, the common types of liquid metals, the basic physical and chemical properties of their multiphase flow and governing equations, etc. Following that, various typical driving modalities and manipulation methods of RTLMs were illustrated. Finally, important implementations ofRTLMs multiphase flow into thermal management, energy harvesting, catalysis, soft machines, biomedicine, and printed electronics were discussed. Overall, the multiphase flow physics ofRTLMs is currently still in its incubation stage and there exist tremendous opportunities and challenges which are worth further pursuing in the coming time.
... The sensors were placed to form a nonintrusive measurement. The ring-shaped is a pair of parallel electrodes with a ring geometry well-established to characterize flow patterns [3]. The electrodes support the RC sensor in sensing changes in electrical parameters (conductance and capacitance). ...
... However, this system exists widely in digestion, catalysis, and fine chemical production [11]. It is limited to measuring the mixing effect of different dimensions and scales by experimental methods [12,13]. Since continuously stirred tank reactors (CSTR) have complex and changeable flow field characteristics, past designs were mostly based on empirical methods [14]. ...
In this study, a solid-liquid mixing system model was established to simulate the coexistence of floating particles (FP) and sinking particles (SP) in the early stage of anaerobic digestion, and the mixing effect and energy consumption of the system were investigated. Four typical blades were selected to compare the solid phase distribution of straw particles under different blade stirring, and the distribution of FP and SP in the coexistence system was clarified. Then the combination of full-factorial design and numerical simulation was applied to compare the effect of blade diameter and blade width on particle mixing, which was better than that of immersion depth. A comprehensive equation was further established to balance the weight between the particle mixing effect and energy consumption and improve the blade design. It provided theoretical support for the design and amplification of subsequent stirring equipment.
... Representative phenomena include blood flow in blood vessels 4 , gas-liquid flow in post-combustion carbon capture processes 5 , oil-gas flow in the energy industry 6 , and micro-fluidic systems in biomedical research 7 . A critical challenge in this field is the quantitative visualization and characterization of the multiphase flow, which is vital to the fundamental study of the underlying fluid mechanics, the prediction and control of the flow response, process modeling, and the safe operation of industrial facilities 8,9 . Although some imaging techniques, e.g., X-ray tomography [10][11][12] and Magnetic Resonance Imaging (MRI) 13 , can be used to provide quantitative flow images, their viability is severely constrained by their limited versatility, scalability, high cost, and non-negligible radiological hazard. ...
Multiphase flow is ubiquitous in nature, industry and research, and accurate flow imaging is critical to understanding this complex phenomenon. Electrical tomography (ET) is a promising technique for multiphase flow visualization and characterization which provides a non-invasive and non-radiative way to unravel the internal physical properties at high temporal resolution. However, existing ET-based multiphase flow imaging methods are inadequate for quantitative imaging of multiphase flows due to inversion errors and limited ground truth data of fluid phases distribution. Here we report a digital twin (DT) framework of ET to address the challenges of real-time quantitative multiphase flow imaging. The proposed DT framework, building upon a synergistic integration of 3D field coupling simulation, model-based deep learning, and edge computing, allows ET to dynamically learn the flow features in the virtual space and implement the model in the physical system, thus providing excellent resolution and accuracy. The proposed DT framework is demonstrated using electrical capacitance tomography (ECT) of a gas-liquid two-phase flow. It can be readily extended to a broader range of tomography modalities, scenarios, and scales in biomedical, energy, and aerospace applications.
... A contactless impedance detection (CID) technique is developed from contactless the conductivity detection (CCD) technique and can realize contactless impedance measurement [16], i.e., can obtain the real part and imaginary part of impedance information simultaneously, and it is available for applying in small channels [17][18][19]. Figure 1 shows the measurement principle of CID. As shown in Figure 1a, the CID sensor is usually composed of an AC excitation source, sensing unit and signal processing unit. ...
In recent years, CID sensors have displayed great development potential in parameter measurement of gas–liquid two-phase flow in small channels. However, the fundamental/mechanism research on the response characteristics of CID sensors is relatively insufficient. This work focuses on the investigation of the influence of separation distance between slugs on the impedance (real part, imaginary part and amplitude) response characteristics of slug flow in small channels. Experiments were carried out with the CID sensors in four small channels with inner pipe diameters of 1.96 mm, 2.48 mm, 3.02 mm and 3.54 mm, respectively. The experimental results show that for a CID sensor, the slug separation distance has significant influence on the impedance response characteristics. There is a critical value of slug separation distance. When the slug separation distance is larger than the critical value, the impedance response characteristics of each slug can be considered independent of each other, i.e., there is no interaction between the slugs. When the slug separation distance is less than the critical value, the impedance response characteristics show obvious interaction between the slugs. It is indicated that the ratios of the critical values to the pipe inner diameters are approximate 100.
... In two-phase applications in which the continuous phase is conductive, the measurement of conductance can be adequate to distinguish the mixture. Shi et al. [25] presented an extensive review of conductance sensors for multiphase flow measurement. As for drawbacks of resistance measurement, one can cite the polarization and corrosion effects due to the need to use electrodes in direct contact with fluids, which may cause misinterpretation of measured data. ...
... In this article, we present a review of capacitive sensors for multiphase flow measurement. This review presents the new developments in the field since the work of Ceccio and George (1996) [27] and may be seen as a complement to the recent works [22], [25]. The objective is to bring an overview of the available measuring principles, with an additional review of the potential application-specific integrated circuits (ASICs) that can be employed in the field, arrangements of electrodes, and measured flow parameters. ...
Capacitive sensors are found in numerous applications, and they are capable of sensing several parameters. Multiphase flows occur in many industrial processes which require proper monitoring to improve the efficiency and safety of plants and equipment. Detailed (high-resolution) flow information is required from dedicated flow experiments at a laboratory scale to develop and validate flow modellings. In both cases, capacitive flow sensors have been applied to have a varying degree of flow detailing, e.g., from simple capacitive probes up to capacitive flow imaging and tomography. This paper reviews the different capacitive sensors applied to multiphase flow measurement and imaging. Operating principles, sensor geometries and capacitive measuring circuits are presented and discussed along with advantages and disadvantages, focusing on flow applications and possible flow parameters yielded from sensors. Some new trends in capacitive flow sensors are also presented.
