Overall contact conductance of a prototype Parallel Fin Thermal Interface

The Parallel Fin Thermal Interface has been developed and tested as an orbital replaceable interface. The interface consists of two identical plates with pairs of opposing parallel straight fins. Each pair of fins is sandwiched between two insert plates pressed against the fins with enough force for good heat transfer through the interface. Two prototype parallel fin interfaces were built (Model 140 and 380) with different fin and insert plate dimensions. Samples of the interfacing surfaces were found to have roughness values ranging from 22 to 35 microinches. Overall interface conductance (Hc) values of 46.7 to 74.2 Btu/hr sq ft-F were obtained for the 140 model in vacuum with an interface pressure from 18.8 to 37.5 psi, respectively. The Model 380 exhibited Hc values from 31.2 to 46.8 Btu/hr sq ft-F in vacuum, with respective interface pressures of 14.2 and 22.0 psi. Several correlations were found to agree with test data to within 20 percent.