Microthermal sensors for determining fluid composition and flow rate in fluidic systems

Schmitt, Bastian; Kiefer, C.; Schütze, Andreas

doi:10.1007/s00542-013-2001-y

Cited by 7 publications

(7 citation statements)

References 9 publications

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“…Nowadays this method is also used in adapted variants, for example, to measure a material and fluid composition or the water content in the skin . In contrast to measurements in extended material samples, however, it is important that the moisture measurement in clothing is limited to a narrow spatial area (or textile layer) and that the wider environment has no influence.…”

Section: Methodsmentioning

confidence: 99%

New Type of Thermal Moisture Sensor for in‐Textile Measurements

Schönfisch

Göddel

Blinn

et al. 2019

Physica Status Solidi (a)

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The measurement of moisture in textile materials worn on or near the skin can be performed for a variety of reasons, for example, to analyze the amount of perspiration in clothing, wound fluid in bandages or even urine in diapers or bed sheets. Conventional moisture measurement methods, such as electrical resistance or capacitance measurement, can be susceptible to cross sensitivities to electrical fields or ionic impurities, often occurring in measurements close to the human body. The very reliable gravimetric methods are too bulky and difficult to be integrated in portable and online measurements. In this paper, the authors present a “transient heat moisture sensor” (THMS) which is small and comparatively easy to integrate into textiles. The authors describe the measurement principle and present a sensor element manufactured with thin film technologies. The analytical description of the sensor fits to both, experimental data and the result of first numerical analysis (COMSOL Multiphysics). The authors demonstrate how to limit the sensors spatial sensitivity to a thin layer of textile without being influenced by the adjacent environment by proper timing of the signal readout.

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Section: Methodsmentioning

confidence: 99%

New Type of Thermal Moisture Sensor for in‐Textile Measurements

Schönfisch

Göddel

Blinn

et al. 2019

Physica Status Solidi (a)

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“…Realisiert wurden die Sensoren durch Sputtern einer ca. 500 nm Bild 1: Layout der untersuchten, mikrostrukturierten Sensoren mit Detailansicht des zentralen Heizers und der vier Temperatursensoren (nach [3]). Der Pfeil symbolisiert die Strömungsrichtung.…”

Section: Messprinzipunclassified

“…Für kurze Heizdauern folgt damit aus Gl. (10), dass für die dem Gemisch zu-geführte Heizleistung P G,F gilt: leitet zunächst unabhängig von der Methanolkonzentration und ermöglicht die Bestimmung der Strömungsgeschwindigkeit unabhängig von der Methanolkonzentration [3]. Basierend auf ihrer Kenntnis soll der Einfluss der erzwungenen Konvektion auf die Temperaturerhöhung des Heizers kompensiert werden.…”

Section: Gauß-förmige Wärmequelleunclassified

“…Bei höheren Flussraten ist der Temperaturanstieg wie zuvor herge-∆T Sensor / °C 10 Vol.−%, 94 ml/h 0 Vol.−%, 94 ml/h 10 Vol.−%, 188 ml/h 0 Vol.−%, 188 ml/h 10 Vol.−%, 0 ml/h 0 Vol.−%, 0 ml/h Math. Modell für 0 Vol.−%, 0 ml/ḣ V = 188 ml/h @ @ RV = 94 ml/h )V = 0 ml/h Gemessener Temperaturanstiegs des Sensors in Strömungsrichtung 2 mm hinter dem Heizer für verschiedene FlussratenV [ml/h] und Methanolkonzentrationen φ [Vol.-%] (nach[3]).…”

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1.2 - Analytische Beschreibung von Hot Disk-Sensoren zur Bestimmung von Methanolkonzentration und Ströungsgeschwindigkeit für Direktmethanolbrennstoffzellen

Schmitt

Schütze²

2014

Tagungsband

Self Cite

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Die analytische Beschreibung eines neu entwickelten Sensor zur Messung binärer Mischungsverhältnisse basierend auf dem sog. Hot Disk-Verfahren wird vorgestellt. Basierend auf der Betrachtung des Heizers als punktförmige Quelle oder als Quelle mit einer bzgl. ihres Mittelpunkts Gauß-förmigen Verteilung der Flächenheizleistungsdichte kann die gemessene Temperaturerhöhung adäquat beschrieben werden. Zusätzlich wird gezeigt, warum im vorliegenden Fall bei einer auftretenden Strömung durch Platzierung eines Temperatursensors hinter dem Heizer und Nutzung der Pulsdrahtanemometrie zwischen Heizer und Sensor die Strömungsgeschwindigkeit unabhängig von den thermischen Eigenschaften des Gemischs bestimmt werden kann.

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“…Inappropriate DEF brakes the SCR or breaks it down and the emission reduction fails. Reported DEF quality sensors are based on optical principles (Kumawat et al, 2014) and electrical (Fendri et al, 2015), ultrasonic (Gurusamy et al, 2017), and pulsed heating mea-surements (Schmitt et al, 2014). These sensors can often solely measure the concentration and sometimes the filling level in the tank.…”

Section: Introductionmentioning

confidence: 99%

Inline quality monitoring of diesel exhaust fluid (AdBlue) by using the 3<i>ω</i> method

Bernhardsgrütter

Hepp

Jägle

et al. 2021

J. Sens. Sens. Syst.

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Abstract. Because diesel combustion processes produce harmful detrimental nitrous oxides, the selective catalytic reduction, an after-treatment method using diesel exhaust fluid (AdBlue) to reduce these emissions, is an important part in the cycle of the combustion process. Therefore, it is crucial to continuously monitor the quality of the diesel exhaust fluid to secure the ideal selective catalytic reduction. This article presents a platinum thin-film sensor using the 3ω method which is able to characterize the diesel exhaust fluid. By means of the 3ω method, information about the concentration of urea in water can be extracted. In this investigation, a digital lock-in amplification technique is used to execute the measurements. The results show that this sensor can determine the urea content within 1 % by weight. Moreover, besides the analysis of the 3ω signal, the 1ω signal is analyzed in depth to receive additional information about the temperature. Because the same structure can measure multiple parameters, such as concentration, temperature, and flow, the sensor might be a good alternative to the state-of-the-art diesel exhaust fluid sensor.

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Microthermal sensors for determining fluid composition and flow rate in fluidic systems

Cited by 7 publications

References 9 publications

New Type of Thermal Moisture Sensor for in‐Textile Measurements

New Type of Thermal Moisture Sensor for in‐Textile Measurements

1.2 - Analytische Beschreibung von Hot Disk-Sensoren zur Bestimmung von Methanolkonzentration und Ströungsgeschwindigkeit für Direktmethanolbrennstoffzellen

Inline quality monitoring of diesel exhaust fluid (AdBlue) by using the 3<i>ω</i> method

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Microthermal sensors for determining fluid composition and flow rate in fluidic systems

Cited by 7 publications

References 9 publications

New Type of Thermal Moisture Sensor for in‐Textile Measurements

New Type of Thermal Moisture Sensor for in‐Textile Measurements

1.2 - Analytische Beschreibung von Hot Disk-Sensoren zur Bestimmung von Methanolkonzentration und Ströungsgeschwindigkeit für Direktmethanolbrennstoffzellen

Inline quality monitoring of diesel exhaust fluid (AdBlue) by using the 3&lt;i&gt;ω&lt;/i&gt; method

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Inline quality monitoring of diesel exhaust fluid (AdBlue) by using the 3<i>ω</i> method