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Keywords: , , , , , , , , , , , , , , , , , , , , , ,

Abstract: The authors look into problems with accurately measuring thermal conductivity of liquid samples. Among these problems is the onset of natural convection during the measurement of thermal properties, which may lead to skewed values reported after characterization. The effect of natural convection is analyzed numerically for the transient hot disk method in order to determine at what time during an analysis the convection causes incorrect output data. The effect of the liquids thermal conductivity, diffusivity, Rayleigh number and Prandtl number on the sensor temperature response is studied. Also, a correlation is developed between the onset of convection and a wide range of Prandtl numbers.

Reference: International Journal of Heat and Mass Transfer 71 (2014) 779-789

DOI: 10.1016/j.ijheatmasstransfer.2013.10.064