4. Experimental setup and methodology
4.1. Experimental setup
Schematic representation of line heat source apparatus used for measuring K is shown in Fig. 1 [14]. The bare wire thermal conductivity apparatus consisted of an aluminum cylindrical sample tube of 104 mm length and 28.4 mm inner diameter, with a removable Teflon cover and with a fixed bottom base cover. A chromel resistance heating wire of 33 gauge and a length of 200 mm stretched between copper leads along the axis of cylindrical tube used as line heat source, of which the effective length of heating element inside the test cylinder is 104 mm and the remaining length (96 mm) is used to connect the leads on either sides outside the test cylinder. A constant DC Power supply was used for all the tests. A pre-calibrated
T-type 28 gauge iron-constantan thermocouple was installed for measuring the core temperature of the sample in the cylinder. The power input to the line heat source was sufficient to give a measurable temperature difference between the time t1 and t2.