Abstract
An array of 30 heat flux transducers (HFTs) has been fabricated and installed in a heat flow meter apparatus in order to measure heat flow across inhomo geneous specimens. Calibration of the individual transducers was accomplished with a 25.4-mm-thick piece of NIST SRM 1450b and a sufficient number of temperature differences to establish a linear relationship between individual transducer output and heat flux.
The HFT array was used to determine apparent thermal conductivity, ka , as a function of position on a test specimen. The measured ka of a foamboard specimen cut to fit into a high-density fiberglass frame was within 2.4% of the ka of the uncut foamboard. The HFT array has also been used to study the change in ka with time of faced and partially unfaced specimens of foamboard insulation. The array was used to monitor changes in ka specimens with 0 to 100% of the facer removed for approx imately five months.
The calibration of the HFT array and the heat flux measurements that have been completed are discussed in this paper. The HFT array provides a way to study the thermal resistance of a specimen as a function of time, temperature, and position.
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