Question

Exercise: Consider an unknown material of the same dimensions as the test section (diameter = 25 mm, length = 30 mm) placed between the brass rods. The voltage and current into the heater are measured to be 9 V and 0.92 A. Once the steady state is reached, the following temperatures are measured: Thermocouples No. T1 T2 T3 T6 T7 T8 Temperature [°C] 62.7 60.7 58.8 20.9 19.0 18.0 Tasks: 1. Compute the power supplied to the heater? We assume that there is no energy loss in the electric 2. Plot the temperature profile along the test rig (from the location of T1 to the location of T8, 3. From the measurements given above, extrapolate the temperature at the two interfaces. Keep irn circuit and that the rig sides are adiabatic. Therefore, there is no loss of heat to the exterior. including the test section) mind that T3 and T7 are located 7.5 mm away from the two interfaces of the test section. We neglect some eventual interface effects 4. Based on the power supplied to the heater, and using the temperature gradients, compute the thermal conductivity of the two brass sections on either side of the test section. Compare it to the value given above. Discuss your findings. Compute the thermal conductivity of the unknown material. 5.

Answer 1

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