Radiative cool down process of porous materials at cryogenic temperatures — design of test set-up

A transient analysis has been presented in this paper for radiative cool down process of open cell metal foams subjected to liquid nitrogen temperatures. Similar to the lumped capacity analysis for a body immersed in a convective medium, a mathematical analysis has been carried out for a body held in vacuum inside an isothermal enclosure. Copper and aluminium foams, having a high porosity of 0.96 and 0.93 respectively, have been chosen for this study. In order to experimentally observe the cool down process, a test set-up has been designed. Preliminary tests have been conducted. The mathematical analysis together with the experimental data can be employed to determine a rough estimate of the radiative geometric feature, that is, view factor of metal foam. Nevertheless, few limitations need to be addressed so as to conduct accurate experimental analysis.