Experimental study of filler insertion effect on mean thermal contact conductance

A series of experiments have been performed to investigate the filler insertion effect on the temperature drop at the wavy contact interface DeltaT and the mean thermal contact conductance h(m,f). Representative behavior of DeltaT against the mean nominal contact pressure p(m) is clarified, and the effect of an interval of time on DeltaT is shown for the silicone filler with thickness delta(fo) = 2 mm. The silicone elastomer is proved effective to increase h(m,f) despite its low thermal conductivity. Further, it is shown that h(m,f) of 0.5 mm thick silicone filler becomes two to three times higher than that of bare contact under the unloading process. However, it is also shown that h(m,f) decreases with increasing delta(fo), therefore filler insertion with improper thickness results in a reverse effect on increase in h(m,f). As for metallic filler insertion using an aluminum or a copper foil, only a little improvement in h(m,f) is obtained in spite of its high thermal conductivity.