Identification of temperature-dependent thermal properties of solid materials

Tillmann, Amanda R.; Borges, Valério Luiz; Guimarães, Gilmar; Silva, Ana Lúcia F. de Lima e; Silva, Sandro M. M. de Lima e

doi:10.1590/s1678-58782008000400001

Cited by 17 publications

(12 citation statements)

References 19 publications

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“…In the first method, presented in Özisik [18], the thermal model is based on nonlinear heat conduction. The second method adopts constant thermal properties within a temperature range to solve the thermal model [19]. Thus, the initial temperature was defined (T 0 ) and the estimation of the properties occurred considering 5 °C as the maximum range of temperature.…”

Section: Methodsmentioning

confidence: 99%

A Different Approach to Estimate Temperature-Dependent Thermal Properties of Metallic Materials

Carollo

Silva

2019

Materials

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Thermal conductivity, λ, and volumetric heat capacity, ρcp, variables that depend on temperature were simultaneously estimated in a diverse technique applied to AISI 1045 and AISI 304 samples. Two distinctive intensities of heat flux were imposed to provide a more accurate simultaneous estimation in the same experiment. A constant heat flux was imposed on the upper surface of the sample while the temperature was measured on the opposite insulated surface. The sensitivity coefficients were analyzed to provide the thermal property estimation. The Broydon-Fletcher-Goldfarb-Shanno (BFGS) optimization technique was applied to minimize an objective function. The squared difference objective function of the numerical and experimental temperatures was defined considering the error generated by the contact resistance. The temperature was numerically calculated by using the finite difference method. In addition, the reliability of the results was assured by an uncertainty analysis. Results showing a difference lower than 7% were obtained for λ and ρcp, and the uncertainty values were above 5%.

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Section: Methodsmentioning

confidence: 99%

A Different Approach to Estimate Temperature-Dependent Thermal Properties of Metallic Materials

Carollo

Silva

2019

Materials

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“…The functions f T ð Þ; g T ð Þ are a priori given functions describing changes of thermal properties under influence of temperature. The functions are determined experimentally and are dependent on the kind of materials [16,17].…”

Section: Formulations Of the Problemsmentioning

confidence: 99%

On temperature and stresses in a thermoelastic half-space with temperature dependent properties

2017

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The paper deals with the axisymmetric problem of the thermoelastic half-space with temperature dependent properties. The thermal coefficients: heat conductivity and coefficient of linear expansion are assumed to be functions of temperature. The mechanical properties: Young modulus and Poisson ratio are taken into account as constants. Two cases of boundary conditions are considered: a normal heat flux acting on a circle with given radius and two variants of the boundary conditions on the outside of the heated region: (1) a thermal insulation, or (2) a constant temperature, taken as reference. The boundary is assumed to be free of mechanical loadings. The linear dependences of thermal properties on temperature is considered as a special case. The obtained exact results are presented in the forms of multiple integrals and the detailed analysis are derived for linear dependences of the thermal properties on temperature.

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“…Esses componentes são o termopar que visto que se encontrou um baixo desvio padrão, uma diferença menor que 2% quando comparado ao valor fornecido pela literatura, e por fim, apresentou ótima repetibilidade, demonstrando que a bancada experimental é confiável. Além destas análises, efetuou-se a comparação destes resultados com os valores obtidos pela técnica apresentada por Tillmann et al [25] . Esta comparação é justificável, pois as amostras utilizadas em ambos os trabalhos tiveram sua condutividade térmica medida pelo IPT [26] .…”

Section: Descrição Da Sonda Linearunclassified

Sonda metálica reduzida para a caracterização térmica de polímeros

2012

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Vários métodos têm sido utilizados na determinação da condutividade e difusividade térmica. Dentre esses, cita-se o Método do Fio Quente, que é muito utilizado por ser um método transiente de troca de calor que determina estas propriedades de forma simultânea e rápida. Neste trabalho o Método do Fio Quente com uma sonda de dimensões reduzidas é usado para obter a condutividade e difusividade térmica do Policloreto de Vinila (PVC) e da Poliamida. Este método se baseia na passagem de uma corrente contínua através de um fio de resistência, gerando calor que aquece uma sonda inserida na amostra. Da dissipação do calor é possível calcular a condutividade térmica. Para determinar a difusividade térmica minimiza-se uma função erro, definida pelo quadrado da diferença entre a temperatura experimental e a numérica. A temperatura numérica é obtida pela solução da equação da difusão unidimensional em coordenadas cilíndricas utilizando o Método de Diferenças Finitas com formulação explícita. O diferencial deste trabalho refere-se às pequenas dimensões da sonda, possibilitando a utilização de amostras menores, além de apresentar um novo dispositivo para fixar corretamente os componentes. Os resultados estimados apresentaram boa concordância com a literatura.

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Identification of temperature-dependent thermal properties of solid materials

Abstract: This work proposes an experimental

Cited by 17 publications

References 19 publications

A Different Approach to Estimate Temperature-Dependent Thermal Properties of Metallic Materials

A Different Approach to Estimate Temperature-Dependent Thermal Properties of Metallic Materials

On temperature and stresses in a thermoelastic half-space with temperature dependent properties

Sonda metálica reduzida para a caracterização térmica de polímeros

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