Transit Time Correlation—A Survey on Its Applications to Measuring Transport Phenomena

Mesch, Franz; Fritsche, R.; Kipphan, H.

doi:10.1115/1.3426838

Cited by 11 publications

(3 citation statements)

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“…The presented methods and described experiment, as well as attached literature, allow to formulate the following proposals: -radioisotopes may profitably supplement traditional method of multiphase flow analysis [15][16][17], -reduction of the necessary assumption demanded for radiotracer experiments allows applying easier measuring procedures and extending their range of application [18][19][20][21][22][23][24][25], -huge development in radiotracer methods, especially in flow velocity measurements, allows both reduction of the radioactivity and increase of the measurements' accuracy [20,[26][27][28][29], -in many cases, application of radioisotopes may bring smaller hazard due to mass of radioisotopes reduction [30][31][32][33], -in some measurements radiotracers may be replaced by sealed radioactive sources [10,16,26] -equipment based on a pair of sealed radioactive sources appeared to be convenient for two-phase flow control [34][35][36], -simultaneous application of tracers and sealed sources gives possibility of more detailed analysis of complex flows [37][38][39][40].…”

Section: Discussionmentioning

confidence: 99%

Improvement of radiotracers experiments in mass transfer processes

et al. 2017

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Abstract. The greatest part of industrial mass transfer is based on continuous transportation of different substances throughout especially constructed installations. In that kind of practice, a flow of such mass in each part determines the process unit and can be described by the residence time distribution (RTD) of the substance inside this unit. This parameter may be evaluated by the properly arranged tracer experiment. It is worthwhile to notice that flow components are labeling for a sufficiently long time for offering a lot of advanced techniques fitted to the particular circumstances.

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Section: Discussionmentioning

confidence: 99%

Improvement of radiotracers experiments in mass transfer processes

et al. 2017

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“…beim Beruhrpunkt zwischen Qxy (z; L ) und der Einhullenden Wxy (z; L ) / X 0 zu suchen. Eine Obersicht der entsprechenden Fragen ist in [18] gegeben. Im allgemeinen sind jedoch die Abweichungen zwischen den verschiedenen Zeiten so gering, insbesondere bei groi3er Signalbandbreite fo und kleiner relativer Geschwindigkeitsstreuung a,/vo , dai3 sie infolge von Meflwertstreuung und weiteren Fehlereinflussen vernachlassigt werden konnen.…”

Section: Stromungsmodelleunclassified

Bestimmung von Transportkenngrößen bei Mehrphasenströmungen mit Hilfe der Korrelationsmeßtechnik

Kipphan

1977

Chemie Ingenieur Technik

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Zur Erforschung von Mehrphasenströmungen sowie zur Auslegung, Überwachung und Regelung von verfahrenstechnischen und chemischen Apparaten ist die Messung von Transportkenngrößen notwendig. Diese Messungen sollten möglichst ohne Störung des Transportvorganges erfolgen. Es wird gezeigt, wie sich dies auf der Basis der Korrelationsmeßtechnik realisieren läßt. Hierbei erfolgt die Bestimmung von Geschwindigkeit, Massenstrom, Turbulenzgrad etc. indirekt über die Messung der stochastischen Konzentrationsschwankungen der dispergierten Phase. Den Meßverfahren liegen theoretische Strömungsmodelle zugrunde. Gerätetechnische Realisierung und automatische Anpassung an den realen Transportprozeß führen auf Meßeinrichtungen, die sich als Labor‐ und Betriebsmeßgeräte einsetzen lassen. Die Anpassung der Verfahren an unterschiedliche Mehrphasenströmungen geschieht über geeignete Meßfühler. Je nach spezieller Meßfühlergeometrie und Anordnung kann die Messung entweder lokal oder integral erfolgen, ebenso ist die Untersuchung instationärer Strömungsvorgänge möglich. Die Erprobung der Meßverfahren wird für Gas/Feststoff‐Blasenströmungen und den hydraulischen Feststofftransport beschrieben.

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“…The time taken by random features of flowing or moving media to be swept past two observation points along the direction of flow can be equated to the time delay position of the function obtained by cross-correlating, for example, flow generated noise measured at the two observation points (Mesch et al, 1974). If the distance separating the observation points is L and the time delay is 7p, then velocity is given by L/rr, .…”

Section: Introductionmentioning

confidence: 99%

A correlation function peak tracking system

Jordan

Manook

1981

Transactions of the Institute of Measurement and Control

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A search and track system for detecting the peak position of a correlation function can be simply implemented and a high resolution result can be obtained. Unfortunately it is difficult to assure industrial users that such a system will only lock on to the most significant peak of the function. In this paper a peak tracking system is described which is forced to search around the most significant peak position by using a second correlator to set the length of the shift register used by the tracking loop. The second correlator must be a digital correlator (eg, the overloading counter correlator) giving a reliable, coarse indication of the position of the most significant peak. I ntroductionThe time taken by random features of flowing or moving media to be swept past two observation points along the direction of flow can be equated to the time delay position of the function obtained by cross-correlating, for example, flow generated noise measured at the two observation points (Mesch et al, 1974). If the distance separating the observation points is L and the time delay is 7p, then velocity is given by L/rr, . In the case of flow velocity a small correction (calibration) factor is required to produce a direct reading instrument.When digital techniques are used to implement the correlation function both the amplitude and time delay axes are quantised. Time delay axis quantisation results from the use of shift register stages to produce the time delay required by the correlation function, ie:where T is the time delay and T the integration period. A long measurement time will result if each point of the correlation function is sequentially measured. Hence a parallel implementation of the function is desirable. Clearly the number of shift register stages that can be used is limited by economic considerations with the result that the resolution of the parallel circuit will also be limited. For example, a peak detected at the 25th shift register stage can be measured with a worst case error of ± 0.5/25, ie 2To if, as is commonly observed, the correlation function is symmetrical. It has been assumed that a long integration period has been set ensue that errors can be ignored. A 201 peak position will require 500 points of the function to be implemented. Although techniques are available to significantly reduce this requirement (eg, by using the overloading counter correlator and a reducing clock frequency along the shift register circuit) (Jordan and Manook) a large number of points of the correlation function must still be measured. A large reduction in circuit complexity results if a peak search and track mode of operation is implemented as shown in the block diagram of Fig 1 (Hayes and Musgrave, 1973). The time delay range is initially searched until the peak is detected at some significant amplitude level at which point the circuit switches to a negative feedback tracking loop configuration. Tracking is achieved by using the differentiated function to provide a positive/negative control signal for the loop. Operation a...

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Transit Time Correlation—A Survey on Its Applications to Measuring Transport Phenomena

Cited by 11 publications

References 0 publications

Improvement of radiotracers experiments in mass transfer processes

Improvement of radiotracers experiments in mass transfer processes

Bestimmung von Transportkenngrößen bei Mehrphasenströmungen mit Hilfe der Korrelationsmeßtechnik

A correlation function peak tracking system

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