Non-invasive measurements of fluids by means of capacitive sensors

Zangl, Hubert; Fuchs, Anton; Bretterklieber, Thomas

doi:10.1007/s00502-009-0612-x

Cited by 3 publications

(6 citation statements)

References 17 publications

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“…In two-phase flow, the permittivity of different fluids is generally different which allows the measurement of the void fraction of the flow components using a capacitance sensor. different types of these capacitance sensors, such as concave [133][134][135], parallel [136], ring [74,[137][138][139], and helical [140] sensors, were successfully used in the measurements of the void fraction/gas holdup in the two-phase flows. The selection of this sensor is because it is simple, easy to implement, and relatively low cost.…”

Section: Capacitance Sensormentioning

confidence: 99%

Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts

2023

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Two-phase gas-liquid and gas-dispersed flows are frequently encountered in the energy, nuclear, chemical, geothermal, oil and gas and refrigeration industries. Two-phase gas-liquid flows can occur in various forms, such as flows transitioning from pure liquid to vapor as a result of external heating, separated flows behind a flow's sudden expansion or constriction, dispersed two-phase flows where the dispersed phase is present in the form of liquid droplets, or gas bubbles in a continuous carrier fluid phase (i.e. gas or liquid). Typically, such flows are turbulent with a considerable interfacial interaction between the carrier fluid and the dispersed phases. The interfacial heat and mass transfer is very important in the modeling of such flows. The variety of flow regimes significantly complicates the theoretical prediction of hydrodynamics of the two-phase flow. It requires the application of numerous hypotheses, assumptions, and approximations. Often the complexity of flow structures makes it impossible to theoretically describe its behavior, and so empirical data are applied instead.The correct simulation of two-phase gas-liquid flows is of great importance for safety's sake and the prediction of energy equipment elements. This Special issue discusses papers related to various aspects of the hydrodynamics and heat mass transfer in two-phase gas-liquid and gas-dispersed flows in pipes or ducts. They can be used as well as in basic sciences and vast applications. Authors from Russia, China, the U.S.A., the U.K., India, and Singapore published their recent contributions for this Special Issue. We are happy to see that all papers present findings characterized as unconventional, innovative, and methodologically new. We hope that the readers of the journal Water can enjoy and learn about experimental and numerical study of two-phase flows using the published material and share the results with the other researchers. In total, 11 papers were presented in this Special Issue (2 of them are reviews and 9 papers are the article) and 3 papers from this list are feature papers.The main goals of this Special Issue are to present the recent advances in experimental and numerical studies of hydrodynamics and heat mass transfer in two-phase gas-liquid and gas-dispersed flows in pipes or ducts for engineering and natural systems that can be very useful for researchers and engineers in heat transfer and heat exchangers communities.

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Section: Capacitance Sensormentioning

confidence: 99%

Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts

2023

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Section: Capacitance Sensormentioning

confidence: 99%

“…Water 2022, 14, x FOR PEER REVIEW 7 of 31 [136], ring [74,[137][138][139], and helical [140] sensors, were successfully used in the measurements of the void fraction/gas holdup in the two-phase flows. The selection of this sensor is because it is simple, easy to implement, and relatively low cost.…”

Section: Capacitance Sensormentioning

confidence: 99%

“…It can measure the capacitance between all possible combination pairs of the electrodes and then estimate the void fraction based on the image reconstruction algorithm. A ring-type capacitance sensor has two ring electrodes separated in the axial direction of the tube [137] and a helical plate capacitance sensor has two helical electrodes [140]. Atkinson and Huang [141] developed mathematical models for the capacitance sensors used in the measurement of the liquid annulus thickness.…”

Section: Capacitance Sensormentioning

confidence: 99%

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Two-Phase Annular Flow in Vertical Pipes: A Critical Review of Current Research Techniques and Progress

Xue¹,

Stewart

Kelly

et al. 2022

Water

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Two-phase annular flow in vertical pipes is one of the most common and important flow regimes in fluid mechanics, particularly in the field of building drainage systems where discharges to the vertical pipe are random and the flow is unsteady. With the development of experimental techniques and analytical methods, the understanding of the fundamental mechanism of the annular two-phase flow has been significantly advanced, such as liquid film development, evolution of the disturbance wave, and droplet entrainment mechanism. Despite the hundreds of papers published so far, the mechanism of annular flow remains incompletely understood. Therefore, this paper summarizes the research on two-phase annular flow in vertical pipes mainly in the last two decades. The review is mainly divided into two parts, i.e., the investigation methodologies and the advancement of knowledge. Different experimental techniques and numerical simulations are compared to highlight their advantages and challenges. Advanced underpinning physics of the mechanism is summarized in several groups including the wavy liquid film, droplet behaviour, entrainment and void fraction. Challenges and recommendations are summarized based on the literature cited in this review.

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“…Das kann sehr zeitaufwendig sein, besonders dann, wenn viele Kombinationen aus Schichtdicke und Leitfähigkeit untersucht werden sollen, zumal feine Strukturen durch entsprechend kleine finite Elemente abgebildet werden müssen. Eine Über-sicht zu diversen kapazitiven Messverfahren für Flüssig-keiten findet sich in [14]. In [1] wird unter anderem die Modellierung von Elektrodenarrays zur medienberühren-den Füllstandsmessung behandelt.…”

Section: Introductionunclassified

2D-Modellierung des Einflusses leitfähiger Schichten auf die Sensorimpedanz bei kapazitiven Sensoren

Weber¹,

Wendler²,

Tahedl³

et al. 2014

Tm - Technisches Messen

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Zusammenfassung:In der industriellen Anwendung kapazitiver Sensoren ist die kontaktlose Detektion leitfähi-ger Schichten flüssiger Medien von Bedeutung. Dabei ist die Sensorimpedanz abhängig von der Frequenz und Eigenschaften des Mediums. Um den Einfluss dieser Parameter zu ermitteln, wurde ein zweidimensionales, rotationssymmetrisches Modell erstellt, mit dem sich eine gute Übereinstimmung mit einer FEM-Simulation erzielen lässt. Aus den durchgeführten Untersuchungen geht hervor, dass sich aus den Parametern eines geeigneten Ersatzschaltbildes ein Maẞ für Leitfähigkeit und Schichtdicke des Mediums ableiten lässt.Schlüsselwörter: Impedanzsensoren, kapazitive Sensoren, Schichtdetektion, analytische Modellierung, FEMModellierung.Abstract: In many industrial applications of capacitive sensors, it is important to detect layers of conductive fluids. The sensor impedance depends on the frequency and properties of the fluid. To determine the influence of these parameters, a two-dimensional, rotationally symmetric model with variable dimensions and material properties is derived. The analytical calculations correspond well with FEM simulations. The parameters of a suitable equivalent circuit can be utilized to approximate conductivity and layer thickness of the fluid.

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Non-invasive measurements of fluids by means of capacitive sensors

Abstract: The paper provides an overview on the applicability of capacitive sensing for non-invasive parameter determination of liquids. Exemplarily, the measurement of void fraction in multi-phase flows, fill level determination, and the estimation of flow velocity are presented.

Cited by 3 publications

References 17 publications

Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts

Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts

Two-Phase Annular Flow in Vertical Pipes: A Critical Review of Current Research Techniques and Progress

2D-Modellierung des Einflusses leitfähiger Schichten auf die Sensorimpedanz bei kapazitiven Sensoren

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