Impact Factorson Effective Pumping Speed of Multi-Layered Insulation Structures in Cryogenic Containers

The effective pumping speed,of the multi-layered insulation materials of cryogenic container after baking at ~100℃,was experimentally evaluated with the lab-built test platform.The influence of the properties of the sandwiched multilayer materials,including,but not limited to the thermal-conductivity/gap-width/number/perforation of the glass-fiber-paper/Al-foil bilayers,and surface cleanliness,on the effective pumping speed of desorbed gas was investigated.The results show that the perforation and bilayer number had a major impact.For instance,as the bilayer-number increased,the effective pumping speed decreased; the longitudinal interlayer gaps were the dominant gas-paths; the apparent thermal conductivity changed in a decrease-increase mode; the perforation promoted interlayer gases diffusion,significantly reducing the axial heat-leakage and weakly affecting the effective pumping speed.We suggest that our preliminary results be of some technological interest in design optimization of cryogenic container.