This paper presents an application of an ultrafast electron beam X-ray CT scanner for investigating the gravitational flow behavior of granulates through cylindrical silo model. The CT scanner allows obtaining crosssectional images of the granular material distribution with a spatial resolution of approximately 1 mm and a time resolution of 2 kHz. In order to conduct a deep analysis of the granular flow concentration changes, two image processing algorithm steps were applied. The first step deals with preprocessing and re-centering stacks of raw images. The second step divides the preprocessed image into several concentric rings and calculates the mean value to study radial concentration changes. Independent analysis of granular concentration in each ring provides useful knowledge to study the silo discharging during mass flow and funnel flow.
Many different methods can be used to monitor the process in the industry. However, the visualization of phase distributions in a wide range of processes is still a challenge. In this paper we would like to present the planar array design of capacitance sensor, which might be used for this purpose in fluidized beds. The developed sensor is 706 mm long, 86 mm wide and consists of 16 x 64 electrodes, what gives 1024 measurement points. It was placed inside an experimental fluidized bed column and applied to monitor flow regimes. During the experiments the sensor was connected to a recently developed capacitance measuring apparatus, which was already evaluated with a wire-mesh sensor. Since the proposed design is expected to reveal changes only by the surface, due to its planar structure, we performed a numerical analysis of sensor sensitivity, as well.
PL
Pomimo opracowania rozmaitych metod monitorowania procesów przemysłowych, wizualizacja rozkładu faz w wielu procesach jest nadal problemem. W artykule autorzy prezentują konstrukcję czujnika pojemnościowego z elektrodami umieszczonymi w jednej płaszczyźnie, który może być wykorzystany w tej postaci do celu monitorowania złoża fluidyzowanego. Wymiary czujnika to 706 mm długości, 86 mm szerokości, rozmieszczenie i liczba elektrod: 16 x 64, co umożliwiło wykonywanie pomiarów w 1024 punktach. Czujnik został umieszczony w eksperymentalnej kolumnie ze złożem fluidyzowanym i użyty do monitorowania reżimów przepływu. W trakcie eksperymentów czujnik podłączono do nowo opracowanego systemu elektronicznego umożliwiającego pomiar pojemności elektrycznej pomiędzy elektrodami. Działanie systemu pomiarowego było już wcześniej testowane z czujnikami siatkowymi. Ponieważ zaproponowana płaska budowa czujnika sugeruje, że jedynie zmiany blisko jego powierzchni będą widoczne, przeprowadziliśmy także analizę numeryczną czułości czujnika.
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We performed wire-mesh and X-ray micro-tomography studies of the two-phase flow in the mixing chamber of an effervescent atomizer. Flow patterns in the mixing chamber can be revealed by the miniature wire mesh sensor with a temporal resolution of 10 kHz whereas microtomography provides accurate and high-resolution axial-radial gas fraction profiles. The paper describes both measurement techniques and first results of experimental investigation.
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A new ultra fast electron beam X-ray CT scanner has been developed, implemented and tested in different applications. It consists, amongst other components, of an electron beam unit with 10 kHz scanning capability and 1 mm focal spot size and a 240 element circular CZT detector arc. The system is capable to produce slice images at up to 7 kHz frame rate of moderately absorbing objects with maximum 120 mm diameter. The paper introduces the scanner and first results for two-phase flow measurements in a bubble column and a fluidized bed.
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In this paper the development of a new thermal control design for a high resolution gamma ray computed tomography detector is presented. The new design has become necessary due to stringent requirements on count rate accuracy under varying thermal conditions at thermal hydraulic test loops. The components of the existing tomography detector have been analysed with respect to their thermal response and a new arrangement has been devised that is optimized with respect to efficient heat conduction from internal as well as external heat sources to a cooling circuit.
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Experimental investigation of multiphase flows plays an important role in many research and industrial sectors. A capacitance wire-mesh tomograph yields high temporal and spatial resolution cross-sectional phase distribution images and is thus well suited for the investigation of two-phase flows. The application of such a tomograph for the investigation of oil-gas two-phase flow in an experimental test facility under industrial conditions is presented and discussed.
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