A thermocouple (0.8 mm OD) is located horizontally in a large enclosure whose walls are at 37?C.

Question:

A thermocouple (0.8 mm OD) is located horizontally in a large enclosure whose walls are at 37?C. The enclosure is filled with a transparent quiescent gas which has the same properties as air. The electromotive force (emf) of the thermocouple indicates a temperature of 230?C. Estimate the true gas temperature if the emissivity of the thermocouple is 0.8.GIVENHorizontal thermocouple in a large enclosureThermocouple outside diameter (D) = 0.8 mm = 0.0008 mEnclosure wall temperature (Te) = 37?C = 310 KGas is enclosure is quiescent and has the same properties as airThermocouple reading (Ttc) = 230?C = 503 KThermocouple emissivity (ε) = 0.8ASSUMPTIONSEnclosure behaves as a black bodyConduction along the thermocouple out of the enclosure isnegligible