Thermal conductivity probe: development of method and application to a coarse granular medium

The author describes the development of a probe method of measuring thermal conductivity k, to enable one to obtain k at times t before the linear domain of probe temperature against ln t is properly established. A variety of probe structures can be accommodated. A probe was constructed and the experimental procedure plus the associated analysis (using a simulation model PROBE) was verified by making measurements on materials of known properties. The technique was applied to an unconsolidated coarse granular medium, a pebble bed consisting of graded river pebbles with equivalent spherical particle diameters 24+or-7 mm, and a bed porosity of 0.396.