Abstract
This study examines experimentally the quality of contact of mechanical
joints in a diode heat sink assembly. Steady-state contact conductance,
h, is used as a quantitative measure of the quality of contact of a
joint. The emphasis of the work is on determining the contact
conductance, h, for a nonideal joint using a noncontact method of
recording temperature distribution in a complex geometry. Thermal
contact conductance for an interface is known to depend on parameters
such as contact pressure, mean interface temperature, and the surface
roughness characteristics of the mating surfaces. The results are
presented for three different conditions of the interface namely
(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 aluminum foil. The results indicate that the
contact conductance increases with the mean temperature of the interface
in all the cases. At low interface temperature, the contact conductance
was greatest for the bare interface conditions. At high interface
temperature, the contact conductance was greatest for the aluminum foil
interface condition.