To determine the thermal conductivity of a structural material, a large 15-cm-thick slab of the material is subjected to a uniform heat flux of 2500 W/m² while thermocouples embedded in the wall at 2.5 cm. intervals are read over a period of time. After the system had reached equilibrium, an operator recorded the thermocouple readings shown below for two different environmental conditions:

From these data, determine an approximate expression for the thermal conductivity as a function of temperature between 40 and 208°C.

Transcribed Image Text:

Distance from the Surface (cm) 0 5 10 15 0 5 10 15 Test 1 Test 2 Temperature (°C) 40 65 97 132 95 130 168 208