COBEM99

SR18 Métodos Experimentais em Termofluidodinâmica

Title:

DETERMINAÇÃO DA DIFUSIVIDADE TÉRMICA UTILIZANDO UM SINAL PERIÓDICO

Summary :

DETERMINATION OF THERMAL DIFUSIVITE WITH A PRIODIC SIGNAL RESUME. THE KNOWLEDGE OF THE THERMAL PROPERTIES OF THE MATERIALS USED IN ENGINEERING IS VERY IMPORTANT FOR SEVERAL SECTORS. ONE OF THE THERMOPHYSICAL PROPERTIES NEEDED IS THE THERMAL DIFFUSIVITY. A TECHNIQUE DEVELOPED BY ANGSTROM, WHICH APPLIES A PERIODICAL SIGNAL IS SHOWED IN THIS PAPER. IN THIS CASE, A PERIODICAL SIGNAL OF HIGH FREQUENCY (BETWEEN 0.01 HZ E 0.25 HZ) IS USED TO DETERMINE THE THERMAL DIFFUSIVITY. TO DETERMINE THIS PROPERTY AN EXPERIMENTAL APPARATUS IS MADE TO MEASURE THE AMPLITUDES AND PHASES OF THE SIGNALS DELIVERED BY THE THERMOCOUPLES INSTALLED AT DIFFERENT POSITIONS OF THE SAMPLE. A POINT OF REFERENCE IS ADOPTED AND THE RATIOS OF AMPLITUDES AND DEPHASAGE ARE CALCULATED. THE RESULTS ARE USED TO IDENTIFY THE THERMAL DIFFUSIVITY IN THE MATHEMATICAL MODEL AND COMPARED WITH THE RESULTS OF THE DIFFUSIVITY MEASURED WITH THE FLASH METHOD. THE COMPARISON PRESENTS A GOOD AGREEMENT. KEYWORDS: DIFUSIVITY, THERMOPHYSICAL PROPERTIES, PERIODICAL REGIME

Author :

Bezerra Filho, Celso Rosendo
Laurent, Michel 0
Lima e Silva, Sandro M. M. de
Raynaud, Martim 0

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