Experimental measurements of thermal conductivity of wood were performed using the heat flow meter and transient plane source technique. The specimens were prepared from five species of both softwoods and hardwoods widely available and used in China, with a wide range of density and moisture content. The transverse thermal conductivity of ovendry specimens is presented as a function of density and temperature up to 90°C and is compared with that along the grain direction for two select species. The influence of moisture content up to 23 percent, which is below the typical fiber saturation point of wood, on the transverse thermal conductivity is presented as well. It is shown that the transverse thermal conductivity of wood increases with density, temperature, and moisture content. Linear correlating equations are proposed in terms of these factors.

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The thermal imaging technique was applied in this work to measure the transient temperature fields during melting of a phase change material (PCM) in a metal foam. A paraffin wax was used as the PCM that was filled in an open-celled copper foam. Melting of a paraffin wax in the presence of copper foam was studied in a rectangular cavity that was heated from one lateral side wall, while the top surface was exposed to an infrared (IR) camera. A thermocouple (TC) was also employed to validate the accuracy of temperature measurements by IR thermal imaging. The relative deviation of measured temperature by the TC and IR camera was found to be under 2% in steady state and under 4% during the entire course of melting. The resolution of IR thermal imaging with the aid of a macro lens allowed for temperature measurements at pore-scale of the copper foam. Local thermal imaging was captured through a minor window on the top plate of the container. Three points (Sp1–3) inside a selected individual pore were marked to quantify the temperature variations of melting process within metal foam/PCM at pore-scale. The average temperature differences between Sp1 and Sp2, Sp3 were found to be about 1 °C over the entire course of melting, and the maximum value was up to nearly 10 °C around the melting point. These preliminary results clearly highlighted the effect of metal ligaments on the temperature distributions at pore-scale.

The bulk thermal conductivity of thin films having a sub-millimeter thickness, made of composite phase change materials (PCM) and utilized as an emerging thermal interfacial material (TIM) for thermal management of electronics, was determined using the transient plane source (TPS) technique. The actual bulk thermal conductivity of the thin film samples was obtained by deconvoluting the thermal contact resistance (TCR) during the measurement process, according to the linear relationship between the nominal bulk thermal resistance and the thickness. The slope of the correlation curve is the reciprocal of film sample thermal conductivity and the intercept is the overall TCR. For the PCM35 thin film samples (which melt at around 35 °C) having three nominal thicknesses of 271±1 μm, 460±2 μm and 511±2 μm, the corrected results in the solid and liquid state were found to be approximately 0.487 W/m·K and 0.186 W/m·K, respectively. It was shown that the corrected values are greater than the direct readings from the TPS instrument as the latter involves the effect of TCR across multiple interfaces. The results obtained in this work could serve as reference property data for design of thermal management systems involving such phase change TIM.