Experimental study on measurement accuracy of hot disk thermal constants analyser

摘要

This work aims at the improvement of measurement accuracy of thermal conductivity and thermal diffusivity using a hot disk thermal constants analyser. The hot disk technique is based on the transient heating of a double spiral plane sandwiched between two pieces of investigated material. By researching the temperature change in the sensor surface, it is possible to deduce both the thermal conductivity and thermal diffusivity of the surrounding material from one single transient recording, provided the heating power and measuring time are appropriately chosen within the reasonable range defined by the theory and experimental situation. Based on the engineering application requirement for precision and efficacy, a new experimental method has been developed for high-accuracy measurement of thermal conductivity and thermal diffusivity in different experimental conditions. The standardized material Pyroceram 9606, with a thermal conductivity of 4.05 W/(mK), has been investigated and analyzed using the newly developed method. The measurement results show that the precision 5% estimated for thermal conductivity and 4% for thermal diffusivity at or around room temperature and under normal pressure, which indicate that the newly developed method has led to the high-accuracy measurement of thermal conductivity and diffusivity.