Thermal conductivity Measurements By Radial Heat Flow Method

A design of a steady-state radial heat flow apparatusis described for the measurement of the thermal conducti vi tyof solid materials over the temperature range OOC to 10000C.Complete analysis of all possible errors is given for thefirst. ti’me and a complete check of the assumptions, usuallymade, in the measurement by this method is made in order tohave the best possible design. Thermal conductivities ofstainless steel and wrought iron were measured on the appa-ratus to calibrate the.apparatus and the obtained resultswere checked within 3% of the. accepted values. The test speci-mens surrounding a cylindrical core hester- were 25 discseach of 10 cm outside diameter and 1.7 cm inside diameter and2 c-m thickness. The five middle discs represent the test aec-.tion and the rest of the discs(lO discs above and 10 discsbelow the test section) represent the end guards. Accordingto comp Le t o error analysis, the· specimen length to radiusratio (L/r) was ch o ae, to be equal 10. TOe permit. the insert-ion of the movable chromel-alumel thermocouples for temperaturemeasurements, eight holes of Jmm diameter were drilled in thetest section discs (four inside at radius 1.35 cm and fouroutside at radius 4.5 cm). Also,.eightJ118tqnsd holes of 4mmdiameter were drilled in the ten upper guard discs.Thermocouples