Abstract
An infrared thermal imaging system is used to record developing
temperature distribution on a diode heat-sink assembly. The quality of
contact of a mechanical joint formed by a diode baseplate and a heat
sink is determined in terms of instantaneous contact conductance, hi.
The results of instantaneous contact conductance are compared with the
corresponding steady-state results obtained in an earlier investigation.
The results are presented for three different conditions of the
interface. These conditions are (i) the mating surfaces are bare, (ii)
aluminum foil is inserted between the mating surfaces, and ( iii) a high
thermal conductivity grease is applied to the mating surfaces. Two
levels of contact pressure are used for the interface with the aluminum
foil. The results indicate that the power input to the diode heat sink
assembly and the condition of the interface determine the duration of
transient analysis needed to closely approximate the parameter of
interest in the steady-state condition. In all the interface conditions
studied and at high power input to the diode heat-sink assembly, it took
only 45 min from the cold start to obtain a variation of less than 10%
between the instantaneous and corresponding steady-state values.