The thermal conductivity is determined by a variation of the line source test method using a needle probe having a large length to diameter ratio to simulate conditions for an infinitely long, infinitely thin heating source. The probe consists of a heating element and a temperature measuring element and is inserted into the specimen. A known current and voltage are applied to the probe and the temperature rise with time is recorded over a period of time. The temperature decay with time after the cessation of heating can also be included in the analysis to minimize effects of temperature drift during measurement. The thermal conductivity is obtained from an analysis of the time series temperature data during the heating cycle and cooling cycle if applicable.
2" x 8"
heat flow; temperature; thermal conductivity; thermal probe; thermal properties