AbstractsBiology & Animal Science

"A transient method for experimentally determining the interface conductance between metallic surfaces in contact is developed. The method applies the theory of negligible internal thermal resistance of one of the materials which form the interface. The method is applicable when the interface conductance is very low, a situation which exists when low conductance interstitial materials are used between contacting surfaces for purposes of thermal isolation. In this investigation, stainless steel wire screens of 10 and 100 mesh were used as interstitial materials between aluminum surfaces in a vacuum environment of 10⁻⁵ to 10⁻⁶ Torr. The interface pressure ranged from 40 to 200 psi. The roughness of the contacting surfaces ranged from 15 to 25 micro inches, root mean square. The experimental results show that the average thermal conductance obtained by the transient method was from 96.04 to 98.5 % of the steady state thermal conductance when the 10 mesh wire screen was used as the interstitial material and was from 79.28 to 91.13 % of the steady state thermal conductance when the 100 mesh wire screen was used. The results thus show that the method of negligible internal thermal resistance is quite reliable for very low interface conductances" – Abstract, leaf ii.