Determination des proprietes thermophysiques de liquides non-Newtoniens a l'aide d'une cellule a cylindres coaxiaux

Bellet, D.; Sengelin, M.; Thirriot, C.

doi:10.1016/0017-9310(75)90139-8

Cited by 54 publications

(38 citation statements)

References 3 publications

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“…Thermal conductivity at various temperatures and water contents were measured using the method described by BELLET et al 4 , based on a cylindrical cell, where the liquid whose properties are determined fills the annular space between two concentric cylinders. The physical characteristic is specified in Figure 1, which presents: two coaxial copper cylinders (a and b), 180 mm in length, separated by a 2 mm annular space, which was filled with the sample; 50 mm thick covers (c) made of a low thermal conductivity material (0.225 W.m -1°C ) to prevent axial heat transfer; a heater made with a constantan wire (resistance 15 W), electrically insulated by a varnish and coiled around a copper stick; two thermocouples type T to measure the temperature differences between the two cylinders, located at half the length of the cell, with wires placed inside 0.5 mm gaps, parallel to the cell axis.…”

Section: Thermal Conductivitymentioning

confidence: 99%

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Rheological and thermophysical properties of blackberry juice

Cabral¹,

Orrego²,

Gabas³

et al. 2007

Ciênc. Tecnol. Aliment.

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Rheological and thermophysical properties were determined for blackberry juice, which was produced from blackberry fruit at 9.1 0.5°Brix and density of 1.0334 0.0043 g cm -3 . The concentration process was performed using a roto evaporator, under vacuum, to obtain concentrated juice at about 60 °Brix. In order to obtain different concentrations, concentrated juice was diluted with distilled water. Rheological measurements were carried out using a Rheotest 2.1 Searle type rheometer. In the tested ranges, the samples behaved as pseudoplastic fluids, and the PowerLaw model was satisfactorily fitted to the experimental data. The friction factor was measured for blackberry juice in laminar flow conditions of pseudoplastic behavior. Thermal conductivity, thermal diffusivity and density of blackberry juice at 9.4 to 58.4 °Brix were determined, in triplicate, at 0.5 to 80.8 °C. Polynomial regression was performed to fit experimental data obtaining a good fit. Both temperature and concentration showed a strong influence on thermophysical properties of blackberry juice. Calculated apparent specific heat values varied from 2.416 to 4.300 kJ.kg -1 °C in the studied interval. Keywords: fruit juice; rheology; thermal conductivity; thermal properties. ResumoAs propriedades reológicas e termofísicas foram determinadas para suco de amora produzido a partir da fruta com 9.1 0.5 °Brix e densidade de 1,0334 0,0043 g cm -3 . O processo de concentração foi realizado utilizando-se um roto evaporador, sob vácuo, obtendo-se o suco concentrado em aproximadamente 60 °Brix. As diferentes concentrações foram obtidas a partir da diluição do suco concentrado em água destilada. As medidas reológicas foram conduzidas utilizando-se o reômetro Rheotest 2.1 do tipo Searle. Em todos os experimentos as amostras apresentaram um comportamento pseudoplástico, e o modelo da Lei da Potência foi ajustado satisfatoriamente aos dados experimentais. O fator de atrito foi medido para o suco em regime laminar com comportamento pseudoplástico. A condutividade térmica, a difusividade térmica e a densidade foram determinadas em triplicata para o suco de amora nas faixas de 9,4 a 58,4 °Brix e de 0,5 a 80,8 °C.A temperatura e a concentração mostraram forte influência nas propriedades termofísicas do suco de amora. Os valores do calor específico aparente variaram de 2,416 a 4,300 kJ.kg -1 °C. Palavras-chave: condutividade térmica; propriedades térmicas; reologia; suco de fruta.

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Section: Thermal Conductivitymentioning

confidence: 99%

“…The cell was calibrated with distilled water. Details of this method, cell calibration and experimental tests can be found elsewhere 4,19,25 .…”

Section: Thermal Conductivitymentioning

confidence: 99%

Rheological and thermophysical properties of blackberry juice

Cabral¹,

Orrego²,

Gabas³

et al. 2007

Ciênc. Tecnol. Aliment.

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“…Thermal conductivity was measured according to the method described by Bellet, Sengelin and Thirriot (1975). This technique uses a cylindrical cell, composed of two coaxial cylinders with an annular space, which is filled with the liquid whose properties are to be determined.…”

Section: Determination Of Thermophysical Propertiesmentioning

confidence: 99%

Thermophysical and rheological properties of dulce de leche with and without coconut flakes as a function of temperature

et al. 2013

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Dulce de leche (DL), a dairy dessert highly appreciated in Brazil, is a concentrated product containing about 70% m/m of total solids. Thermophysical and rheological properties of two industrial Brazilian Dulce de leche formulations (classic Dulce de leche and Dulce de leche added with coconut flakes 1.5% m/m) were determined at temperatures comprised between 28.4 and 76.4 °C. In general, no significant differences (p < 0.05) were observed in the presence of coconut flakes in the two formulations. Heat capacity varied from 2633.2 to 3101.8 J/kg.°C; thermal conductivity from 0.383 to 0.452 W/m.°C; specific mass from 1350.7 to 1310.7 kg/m³; and, thermal diffusivity from (1.082 × 10-7 to 1.130 × 10-7) m²/s. The Bingham model was used to properly describe the non-Newtonian behavior of both formulations, with yielding stress values varying from 27.3 to 17.6 Pa and plastic viscosity from 19.9 to 5.9 Pa.s.

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“…Equation (1), as described by Bellet et al (1975), can be used to calculate the sample thermal conductivity, λ from the experimental measurements of T 1 and T 2 under steady state conditions. ).…”

Section: Determination Of the Freezing Point Depressionmentioning

confidence: 99%

Effect of maltodextrin on the freezing point and thermal conductivity of uvaia pulp (Eugenia piriformis Cambess)

et al. 2012

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The freezing point depression (FPD) of uvaia pulp with and without additives -10, 16, 22 and 28% of maltodextrin (MD), was measured using a simple apparatus consisting of two major sections: a freezing vessel and a data acquisition system. The thermal conductivity of the pulps was also investigated as a function of the frozen water fraction and temperature using a coaxial dualcylinder apparatus. Above the initial freezing point, thermal conductivity fitted the polynomial equations well. Below the freezing point, thermal conductivity was strongly affected by both the frozen water fraction and the temperature. Simple equations in terms of the frozen water fraction and temperature could be fitted to the experimental data for freezing point depression and thermal conductivity.Indexing terms: Freezing point depression, uvaia pulp, thermal conductivity. RESUMOO ponto de início de congelamento (FPD) da polpa de uvaia com e sem aditivos -10, 16, 22 e 28% de maltodextrina (MD), foi medido por um aparelho simples, que consiste de duas seções principais: um vaso de congelamento e um sistema de aquisição de dados. A condutividade térmica foi calculada em função da fração de água congelada e da temperatura, usando um aparelho cilíndrico coaxial duplo. Foram empregadas equações polinomiais para descrever o comportamento do ponto inicial de congelamento e da condutividade térmica. Abaixo do ponto de congelamento, a condutividade térmica foi fortemente afetada pela fração de água congelada e pela temperatura. Equações simples em termos da fração de água congelada e da temperatura podem ser ajustadas aos dados experimentais no cálculo do início do ponto de congelamento e da condutividade térmica.Termos para indexação: Ponto de início do congelamento, polpa de uvaia, condutividade térmica.

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Determination des proprietes thermophysiques de liquides non-Newtoniens a l'aide d'une cellule a cylindres coaxiaux

Cited by 54 publications

References 3 publications

Rheological and thermophysical properties of blackberry juice

Rheological and thermophysical properties of blackberry juice

Thermophysical and rheological properties of dulce de leche with and without coconut flakes as a function of temperature

Effect of maltodextrin on the freezing point and thermal conductivity of uvaia pulp (Eugenia piriformis Cambess)

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