Document IIF

Mesures des coefficients de transfert de chaleur locaux des produits alimentaires utilisant une méthode calorimétrique in situ.

Measurement of local heat transfer coefficients on food products using an in situ calorimetric method.

Résumé

In this work, an in situ calorimetric method was investigated to measure local heat transfer coefficients on vegetables submitted to freezing processes. Three products were used: tomato (sphere), French courgette and green beans (cylinder). The air speed conditions employed were respectively, 0 (natural convection), 1, 3, 5 and 7 m/s. To validate the measured coefficients, two other methods were employed. One was based on the replacement of the products by copper bodies (tomato and courgette) and by acrylic cylinders (green beans) of same geometry and reproduction of the other experimental conditions. The coefficients were obtained by regression analysis of the cooling curves. The second method estimated the coefficients by using relations of the type Nu= f(Re). The values measured by in situ calorimetry are in accordance with those obtained by the other methods. Moreover, the calorimetric method enables the measurement of local values, while the others result in an overall coefficient. The coefficients obtained for green beans were used for the simulation of the freezing time employing a numerical enthalpic finite difference method. Simulated curves fitted well to experimental ones.

Documents disponibles

Format PDF

Pages : ICR07-C2-730

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Détails

  • Titre original : Measurement of local heat transfer coefficients on food products using an in situ calorimetric method.
  • Identifiant de la fiche : 2008-0737
  • Langues : Anglais
  • Source : ICR 2007. Refrigeration Creates the Future. Proceedings of the 22nd IIR International Congress of Refrigeration.
  • Date d'édition : 21/08/2007

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