The apparatus of Fig. 9.3 is used for measurement of the thermal conductivity of an unknown metal. The lengths of the unknown and known bars are the same, and five thermocouples are equally spaced on each bar. From the temperature and heat-flux measurement the thermal conductivity of the unknown is to be established as a function of temperature. Design the apparatus to measure the thermal conductivity of a material, with k ∼ 100 Btu/h · ft · ?F. Consider the influence of thermocouple spacing, dimensions of the bars, heat-flux measurement, and temperature measurement on accuracy. Take the thermal conductivity of the known material as exactly 20 Btu/h · ft · ?F.
