Search

A novel thermal non-destructive technique based on a Pulsed Flying Spot is presented here by considering in-plane logarithmic processing of the relaxing temperature field around the heat source spot. Recent progress made in optical control, lasers, and infrared cameras permits the acquisition of 2D temperature fields and localized thermal excitation on a small area instead of the entire recorded image. This study focuses on a new method based on spatial logarithm analysis of a temperature field to analyse and measure different parameters, such as the in-plane thermal diffusivity and localization of the spot. In this paper, this method is presented and the first results of heterogeneous anisotropic materials are depicted. The in-plane thermal diffusivity is estimated with an error lower than 4%, and the initial location of the heating spot is determined. [ABSTRACT FROM AUTHOR]

This work aims to achieve contactless absolute-temperature measurements of infrared-semi-transparent solids using an infrared thermal and spectroscopic imaging technique. The multispectral thermotransmittance coefficient fields in the 3-5 lm wavelength range for Sapphire, KBr, and Silicon are determined to be 6x10-4 K-1, 4x10-4 K-1, and -3x10-3 K-1, respectively. The most interesting result is the high temperature-dependent transmittance coefficient in the middle wave infrared region. With these coefficients, the absolute temperature fields in a range from room temperature to 140°C are shown. [ABSTRACT FROM AUTHOR]

The present work presents a fast and simple new experimental method, designed to enhance the observation and characterization of thermal phenomena at microscale. Supercooling of water was carried out in micro-channels and recorded with a high-frequency infrared camera. The method is based on the coupling of microfluidics, infrared thermography, and inverse techniques. The objective is to extract a maximum of information from the experiment to perform advanced characterization of the system. First, a thermal modeling of such a system was written, then the image processing from infrared recordings allowed estimating the thermal properties (diffusivity) and the source term (energy released by the phase change). The novelty of the approach is the ability of measuring the heat released by the phase change and using this displacement to calculate the ice front propagation velocity and thermal properties. This method is appropriate for many other applications and is mainly devoted to the characterization of fluids during phase change at microscale. [ABSTRACT FROM AUTHOR]