Browsing by Author "Braga, Sergio"

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    A study of cooling rate of the supercooled water inside of cylindrical capsules
    (Scopus, 2009) Braga, Sergio; Milón Guzmán, Juan José; Jiménez Pacheco, Hugo
    An experimental apparatus was developed to investigate the supercooling phenomenon of pure water inside cylindrical capsules used for cold storage process. The Phase Change Material (PCM) used was distilled water. The external coolant material was a water-alcohol mixture (50% vol.), controlled by a constant temperature bath (CTB) in four fixed values (-4 °C, -6 °C, -8 °C, and -10 °C). Temperatures varying with time were measured inside and outside the capsule. Cylindrical capsules with internal diameter of 30 mm, 45 mm, and 80 mm, with 1.5 mm wall thickness were made in aluminum, bronze or acrylic materials. The Cooling Rate (CR) was investigated for different positions on the internal wall of the capsule, for different external coolant temperatures (Tc), different capsules diameters and different materials. The results showed that the cooling rate is a strong function of the angular position on the internal wall, the coolant temperature, the capsule material, and the capsule's diameter. © 2008 Elsevier Ltd and IIR.
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    Supercooling water in cylindrical capsules
    (Scopus, 2005) Milón Guzmán, Juan José; Braga, Sergio
    An experimental apparatus was developed to investigate the supercooling phenomenon of water inside cylindrical capsules used for a cold storage process. The coolant is a water-alcohol mixture controlled by a constant temperature bath (CTB). Temperatures varying with time are measured inside and outside the capsule. Cylinders with an internal diameter and thickness of 45 and 1.5mm, respectively, were made from four different materials: acrylic, PVC, brass, and aluminum. The supercooling period of the water and the nucleation temperature were investigated for different coolant temperatures. The supercooling and nucleation probabilities are shown as a function of the coolant temperature for the four different materials. © 2005 Springer Science+Business Media, Inc.
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    Visualization of dendritic ice growth in supercooled water inside cylindrical capsules
    (Scopus, 2012) Braga, Sergio; Milón Guzmán, Juan José
    An experimental device was developed to study dendritic ice growth in supercooled water inside cylindrical capsules. The capsule materials investigated were acrylic, PVC (polyvinyl chloride), bronze and aluminum. The internal diameter of all the capsules was 45 mm. The results indicate that dendritic ice appears only in supercooled water at the start of nucleation. Blockage by dendritic ice growth was classified according to the capsule material and the coolant temperature. Total blockage (100%) and partial blockage (25%, 50% and 75%) was observed. Dendritic ice growth was shown and analyzed in photographic sequences. © 2012 Elsevier Ltd. All rights reserved.