Thermocouple probe is the effective part which measures the
surface temperature. Thermocouple wires interact with environment
and transfer heat to (or from) the surface and alert the
measured temperature [25]. Therefore, the probe measures the
disturbed temperature not the actual surface temperature. Consequently,
the temperature distribution along the thermocouple
junction and wire can be analysed by considering them as a stepped
fin [26,27], see Fig. 8. The thermocouple wires represented by the
single wire model (see Section 3.1) were considered to be a very
long fin while the thermocouple junctionwas considered to be a fin
with prescribed end temperature [21]. Therefore, the junction
temperature distribution can be calculated from Eq. (13) for the
length 0 x Dp: